Darn, I like that too but it is too expensive for what you get.
People will be selling these on eBay soon, that would be the only reason to get one but even then what profit could you make in good conscience?
I would pay probably $120 for the signed one, that i what it should have been but getting close to launch this is when they know they can hype the prices.
An acquaintance of mine who is my local GameStop manager is going to PAX East and is going to try and get a poster signed for each of us by Ken, I hope he succeeds
EDIT: I'm not even sure if Ken signed those books or not, none of them look like his sig (maybe the really scribblly one but it doesn't really resemble the one from the posters). If Ken (who it says wrote it) didn;t sign it then it defiantly isn't worth it... as if it doesn't tell you who specifically signed it, it just says "Signed by the authors and artists".
After looking more i guess the Scribbly one is his...