Edit: I am no longer playing WoW so my guide will not be updated by me again, but I will leave it here. A very big thank you to every one for your contributions to this thread and guide.
The Complete 49 Boomkin Guide
Welcome fellow Boomkins!
Although rather rare, Boomkins are known for their tremendous burst damage and all around support; whether it be DPS or healing, a Boomkin can help!
Pros of a 49 Boomkin
-Very high burst damage; heavy dps support
-Unique support abilities - Roots, Innervate, Hibernate, Remove Curse, Faerie Fire, etc
-Excellent support class
-Can also hold their own well in 1v1s
Cons of a 49 Boomkin
-The burst damage is some-what reliant on RNG, i.e. Starfire crits
-Easily shut down by Melee + other classes
-Very limited of escapes and "oh shit" buttons
-Goes OOM quickly
+ Race +
+ Professions +
+ Gear - Enchants +
+ Additional Gear - Notes +
+ Glyphs +
+ Talents +
+ Macros +
+ Basic Overall PvP Tips +
+ Basic PvP 1v1 Tips +
Race
There really is no better choice for Druids in this bracket, both the Tauren, and the Night Elf racial are amazing. Enough said. 
Professions
Jewelcrafting and Leatherworking are pretty much the best choices for professions. The Tribal Leatherworking leggings you get from Leatherworking are pretty much best in slot and the JC Ruby Serpent trinket is almost too good to pass up. I guess you could go Engineering instead of Jewelcrafting if you want, I wouldn't, but that's just me.
Tribal Leatherworking: Check out the Wowhead quest comments for a how-to on how to get Tribal Leatherworking.
Wowhead: Tribal Leatherworking Quests
Wowwiki: Wowwiki on Leatherworking - Scroll down to Tribal LW!
Gear
The gear is listed from most common to rarest - Obviously BoE items depend on your server's Auction House.
* = most commonly used
A lot of the gear depends on personal preferance on how you want to gear your Boomkin.
Head:
*Eye of Flame
Soothsayer's Headdress
Soulcatcher Halo
Neck:
*Pulsating Crystalline Shard
Lei of Lilies
Gemshard Heart
Shoulder:
Living Shoulders
*Kentic Amice
Mantle of Lost Hope
*Preended Ironfeather Shoulders
Back:
Horde only:Deep Woodlands Cloak w/ 20 Spell Penetration
*Spritecaster Cape w/ 20 Spell Penetration
*Featherskin Cape w/ 20 Spell Penetration
Chest:
*Flamestrider Robes w/ 6 stats
Chan's Imperial Robes w/ 6 stats
Wrist:
Dryad's Wrist Bindings w/ 15 Spell power
Weapon:
*Devout Aurastone Hammer w/ 30 Spell power - Click here to view stats
Dignified Headmaster's Charge w/ 30 Spell power - Click here to view stats
Horde only: Enchanted Azsharite Felbane Dagger w/ 63 Spell power
Horde only: *Enchanted Azsharite Felbane Staff w/ 81 Spell power
*Kindling Stave w/ 40 Spellpower
Zum'rah's Vexing Cane w/ 40 Spellpower
Glowing Brightwood Staff w/ 30 Intellect
Blade of Eternal Darkness w/ 40 Spellpower
Off Hand:
Enthralled Sphere
Drakestone of the Eagle/Healing
Cloud Stone
Gloves:
*Ogreseer Fists w/ 20 Spell power
Atal'ai Gloves of the Eagle/Healing w/ 20 Spell power
*Bloodfire Talons w/ 20 Spell power
Belt:
*Satyrmane Sash
*Ban'thok Sash
Chloromesh Girdle
Leggings:
*Wildfeather Leggings (Please see Leatherworking above in Professions)
*Necromancer Leggings
*Imperial Red Pants
Windscale Sarong
Spellshock Leggings.
Boots:
Vinerot Sandals w/ *Surefooted or *Boar's Speed or 12 Stamina
*Archaeologist's Quarry Boots w/ *Surefooted or *Boar's Speed or 12 Stamina
Rings:
*Underworld Band
*Freezing Band
*Cyclopean Band
Gem Studded Band
Mindseye Circle
Deadman's Hand
Trinkets:
*Insignia of the Horde - *Insignia of the Alliance
Defiler's Talisman
*Figurine - Ruby Serpent (Jewelcrafting)
Discerning Eye of the Beast (17 Spellpower)
*Tidal Charm
Arena Grand Master
Additional Gear + Notes- Get Green Whelp Armor and put either 100 HP on it or 100 Mana
- Try to aim for at least ~2.7k-3k HP, ~250-300 spell power. Personally, I try to never go below ~300 Spell power just because I like big numbers.
It all depends on how you want to gear your Boomkin, whether you want to stack Spell power, or stats, or just have a good balance of the two.
- Lei of Lilies - You don't have to have the Lei of Lilies necklace on to use the conjured item. I always conjure a new lilie whenever I log on!

- Make getting a Tidal Charm a high priority. 1v1s become SO much easier to deal with, with a Tidal Charm.

- If you have the money pick up 2 additional Dryad's Wrist Bindings and put 12 Intellect on one and 12 Stamina on the other.
- Pick up a Helm of Fire if you can get one for cheap. It's good to include in your burst rotations since it got buffed.
Glyphs
I currently use the Healing Touch, Insect Swarm, and Dash glyphs, but all the gylphs I have listed are viable. If you want to test out the other gylphs, I would recommend not dropping Insect Swarm, but it's really up to you. 
Major:
Healing Touch - If you're always caught in heavy crossfire, and needing to heal a lot, you might want to invest in this trusty glyph. Fantastic glyph in my opinion.
Insect Swarm - The most powerful Boomkin glyph for the bracket in my opinion
Barkskin - Amazing glyph that can save your life from those nasty crit happy Ambush Eviscerate Rogues or MS Warriors.
Innervate - A good glyph to pick up if you're not focused or targetted at all.
Moonfire - Mainly a PvE glyph, but combined with the Insect Swarm glyph, your 2 dots will be rackin' up some serious damage. The only downside is that you won't be able to burst down people with Moonfires when they get low.
Overall outstanding glyph but very very situational.
Regrowth - If you're happy with just Regrowth and Rejuv, you can pick this glyph up instead of the Healing Touch glyph.
Wrath - Another decent and viable glyph.
Entangling Roots - Basically makes roots more reliable.
Minor:
Aquatic Form - If you play a lot of AB, and play it more than WSGs and Arenas, you might want to try this out. 
Dash - Lowers your Dash cool down to 2 minutes and 24 seconds
Talents
Disclaimer: Some of this information is based on my personal beliefs and opinions. >.<
There are a few key talents which I believe all Boomkins should consider picking up, some are obvious then others.
I won't list the super obvious ones like Starlight Wrath and Vengeance. 
Improved Moonfire - Some people don't pick up this talent, but Moonfire crits are nice damage, and you'll proc Nature's Grace more with this too!
Nature's Majesty and Nature's Grace - 2 extremely critical talents for a Boomkin. With Nature's Grace and Wrath, you can catch a lot of people off guard with it, especially healers!
All it takes is a single crit or 2!
Lunar Guidance - 12% more Spellpower depending on your Mana.. more spell power.. I like! 
Improved Moonkin Form - I have 197 Spirit, so this gives me 59 more Spell power when I shift into Moonkin Form. Pretty much a must-have for people who want a good amount of Spell power.
Builds:
(The 1 extra point after you pick up Nature's Majesty and Improved Moonfire can be placed in either Moonglow, or Genesis, you pick.)
Regarding Dreamstate: I know some Boomkins pick up Dreamstate, and I know Dreamstate isn't bad, but if you're going for hits/crits, you can afford to not spec into it.
Full Balance 40/0/0 - The typical cookie cutter spec. - The 5 talent points in the 8th tier are in a decent spot. You could always take out 2 points from Wrath of Cen. and put them in Owlkin Frenzy or where ever. You could also take 1 point out of Moonglow and put it in Brambles. It's really up to you and how you're going to build your Boomkin.
Talent Calculator - World of Warcraft
Balance 37/0/3 - This build is also very viable, you lose a little bit of crit damage but in return you get 70% reduced pushback on your critical abilities.
Talent Calculator - World of Warcraft
Got a build you'd like to share? I'm always up for the discussion of ideas for new/different builds!
Macros
I really only use Innervate and Prowl now, I used to use all mouseover heals and abolish. I'll put them all here too.
Innervate - Casts Innervate on yourself then equips your Soulkeeper
Code:
#showtooltip Innervate
/cast [target=player] Innervate
/stopcasting
/equip Soulkeeper
Prowl - Immediately switches to Cat form and prowls
Code:
#showtooltip Prowl
/cast [nostance:3] Cat Form; [stance:3, nostealth] Prowl
Mouseover Rejuv
Code:
#showtooltip Rejuvenation
/cast [target=mouseover,exists,help,nodead] Rejuvenation; Rejuvenation
Mouseover Regrowth
Code:
#showtooltip Regrowth
/cast [target=mouseover,exists,help,nodead] Regrowth; Regrowth
Mouseover Abolish Poison
Code:
#showtooltip Abolish Poison
/cast [target=mouseover,exists,help,nodead] Abolish Poison; Abolish Poison
Mouseover Remove Curse
Code:
#showtooltip Remove Curse
/cast [target=mouseover,exists,help,nodead] Remove Curse; Remove Curse
Basic Overall PvP Tips
Boomkins can be a tough class to learn and get the hang of at first. The 49 bracket is a harsh, unforgiving bracket for players who are learning their class. Mistakes can cost you big.
But once you learn... doors will open. You will be feared among the battlegrounds!
I'll try to keep the tips brief and to the point.
-Wrath is better dps than Starfire.
-Basic rotation usually includes some thing similar if not equal to: Insect Swarm -> Moonfire -> Roots (depending on class) -> Wrath or Starfire depending on situation. 
-Do not underestimate Starfire stun. Period.
-Chug-a-lug chug-a-lug! Drink whenever you're out of combat! You need to start every fight will all your mana. Always keep a lot of water.
-Cover your dots with Faerie Fire against Priests/Paladins.
-Always try to use Nature's Grasp last in a 1v1, only use it if you can't get a root off any other way.
-Don't stay out of prowl for too long! Wandering around out of prowl is a bad habit to get into. It basically lights up a big green glowy neon sign over your head that says FOCUS FIRE ME! Always lay low until you're ready to strike. The only real exception is when your fighting a Rogue 1v1. You are not a Mage, don't try to play like one.
-Get lots of bandages and use them!
Moonfire: No matter what people say about how cheap Moonfire spam is and how noobish it is; It IS a viable tactic to "run and gun", (repeadedly moonfire some one while running away from them) in a lot of 1v1 situations, you would (obviously) lose DPS if you didn't, all melee can pretty much do absurd amounts of burst to you at any given moment, not DPSing hard enough can easily cost you the fight. So Moonfire away! Just watch your Mana because if you Moonfire too much, you will go OOM fast.
Try not to Moonfire spam healers either!