I had both. PS2 is better cause you got more games. Xbox has better graphics and you dont need a memory card, cause it has HD.
I would still go with PS
i own a ps2 and my roomy has an xbox... i like the xbox games better, theres less loading time... depends though. You can mod the shit out of an xbox and store like 30 games on the HD and the 4 controllers is key too... playing Halo or NHL or whatever with 4 ppl is awesome