I have a few games that need playing, but not that many that i play for a while, and then just toss tot eh side when a new one comes out, because i just end up buying games and not playing them as i just get them when they are at good prices weather i need them or not. Having said that, i do have a few titles i need to go back and complete:
Pikmin
POP:WW
Halo 2 (if i can be bothered, 1 player doesn't exactly captivate me)
COD2 (been playing on veteran, stopped playing it because of oblivion, and now i can't even do it on veteran now!)
Majora's Mask (i keep playing through it, and then losing interest - probably will never get completed as i have to many games to play!)