oh wow i would fucking love it! any of my games would be from to dive into.
FFVII - join cloud and his party to save the world... i would totally level up with aries and tifa

... i would steal cloud's sword too... and discover a way to revive arieth! white chocobo here i come!
NHL09 - hell yea i would "be a pro", love hockey, havent played for years... would become lead forward for the San Jose Sharks
Rock Band 2 - Endless Setlist forever!
Skate 2 - ok this one i would have trouble with b/c i rollerblade... eh worse comes to worse i'll just kick ass in hall of meat contests
Any MMORPG - would become the highest level and most powerful PKer ever! (Sora! .hack what up!?)
Silent hill - ... fuck me. i'd go insane in order to survive longer.
PORTAL - haha i would find that damn cake and eat it too! (or just get stuck in an endless loop of two portals... weeeeeee!)
Resident Evil - Zombies be damned! ... Jill Valentine... I'd totally hit that
MetalGearSolid - evil fun with stealth camo... and i would mind having raiden's abilities (in MGS4 of course)
Wolfenstein 3d - If i can bring a cd with me and my Metallica Black cd... hells yea kick some Nazi ass all day long... Guten Tag my Chaingun MoFo!
Little Big Planet - How could anyone not have fun being trapped in this world!?