Well, I don't know. I suppose it depends on what you're looking for. Off the top of my head, here are some of my favorite N64 games:
-Smash Bros.
-Mario 64
-Perfect Dark
-Mario Kart 64
-Zelda: Ocarina of Time
-Beetle Adventure Racing
Basically, if you don't need fighting games, RPG's, or (good) sidescrollers, snatching up an N64 and a couple games isn't a bad idea.
I'd wait for GameCube though. It's just around the corner (relatively speaking) and looks to have a more diverse game line up.
Of course, being a sidescroller fan and owning an N64 meant going back to the old SNES fairly often to get my "sidescroller fix."
Hope that helps! :D