The cream of multiplayers from my collection are:
WE7 (Or any WE/PES game really)
Tony Hawk 3 (I have THUG2 too, but am not sure how many players it is)
IMO the greatest multiplayer games of all ... Man, the guy standing next to me just let rip like he'd exploded! ... Sorry, back on track... are Bishibashi Special 1/2. I just love those games so much and anyone can pic them up and play them, so you don't really need to worry about people having to learn how to play. Great game! If you can get Bishibashi Special Step-Champ, that's a cracker too. For that though you need the DDR mats for the floor, but a great party game! They're actually all PS1 games, but they work on the PS2. Swallow your pride and buy them, you know you want to!