I'm going to jump on the Shipwrecked love bandwagon as well. It's pirate metal, what's not to love? It's a lot of fun on all instruments too.
If you're looking for a fun yet challenging keys song and have liked Amberian Dawn's offerings so far, I recommend Pythia's Heartless as well.
Not much else I can add for 2012 since I'm on the PS3, and don't want to recommend anything I haven't played yet myself.
I've recently bought a couple of the Jerry Naylor tracks (50's rock and roll), Sunny Side Up tracks (ska), and "Bigger Than Kiss" (discusses the merits of beating the piss out of Peter Criss).
I'm still trying to pull the trigger on the Alestorm stuff. I fear that it is a bottomless hole which will lead to an eventual loss of morals and general regard for society, and once I buy one, I'm going to have to buy all.
My favorite release's would be LTJ 's Younger lungs, MC Lars This Gigantic Robot Kills, and all the A Day to Remember songs
RockBand Needs :
NOFX, Less Than Jake, Lagwagon, Strung Out, and The Vandals
All the chaotrope stuff. And that s/h(im)e[r] one. Devin townsend stuff was pretty cool too. Also the solution .45 stuff.
430 songs, X Drums
Last DLC Bought: Child in Time by Deep Purple
Last RBN Bought: Widower by The Dillenger Escape Plan
"Fire has other worldly powers" -Lawdog1521
I've bought a crapton of songs so far this year (and no I don't buy everything).
There's been a lot of awesome stuff come out and it's only been three months! O_o
Check out the TAG website here! :
My favorites are Animal Instinct, Brains Out, Visceral, Gravitational Lensing, Clawmaster, M.O.N.O.S., Flesh and Blood, Baptised, and Liberation.
 Dizzy Mizz Lizzy  Dover  Guano Apes  More Miley Cyrus
 The Rasmus  The Veronicas  More Volbeat