[quote name='CocheseUGA']*Notices the standard arcade carpet*
Damn, this is a tough choice to make. On one hand, the game kicks so much ass (what are perks, btw?), and I've gotten not-great sleep for three nights in a row.[/quote]
Perks are sort of like power-ups. When you create a class, you get to choose three perks, one from each category. Category one has things like get 3 special grenades (stun/flash/smoke), get 3 frags (last one you get), get and RPG, get two claymors, and get two C4s.
Category 2 has things like a health boost and extra bullet damage.
Category 3 has things like martyrdom (drop a live nade when you die) and one where you can sprint for longer.
You unlock them as you level up. I don't remember many of them as I usually use the same set, so check 'em out for yourself and decide which are best for your set. :]