Gears of war 2 "game of the year" release?

[Fatboy]

I got the original gears 2 and im thinkin about gettin the new one..but i got some doubts...first....how much do u think i can get for gears 2 if i trade it in (storecredit, not for cash)? and second...will i be able to play ppl who have the original gears 2? (eg. on the playstation 2...gta san andreas and gta san adreas "greatest hits"...how u cant load ur original gta saved game data becuz its not compatible)...it comes out 2morro i think so plz let me knw..