Wow. That's... that's a big list. Just looking at it is making me nauseous.

It all depends, of course, on how deeply into the story you care to delve. The main book is likely all you REALLY need, and maybe Front Line. The Amazing Spider-Man trade is where the bulk of the fallout from CW #2 is explored, but otherwise, it's basically a case of which characters you like and want to see more specific fallout for. If you don't care for Thunderbolts or Ms. Marvel, you're not really missing anything in the main tale by not delving into their respective tie-in trades. I, however, have already got the majority of them pre-ordered through DCBS. :)