I just picked up this game recently (yeah, yeah...a little late, I know) and it really does live up to the hype! I also own an Xbox and the graphics in GTA3 hold their own and even excell on the inferior PS2 hardware.
The freedom of the gameplay sucks you in for hours at a time just driving around the city causing havok. Games like GTA3 only come around once in a long while, so if you own a PS2 be sure to add this one to your library. An easy 10 out of 10 and quite possibly the best game on the PS2.
PS - This game is not suited for any young 'ens. It really does earn that "M" rating.