Well, the most common and popular picks have already been mentioned i guess i'll only add a couple more games
International Superstar Soccer 64 (or 98, never played 2000 so i dont know if its as good), easily one of the best goddamn futbol/football games ever made, its not liscenced by Fifa but one of the quirky things the 98 version had is that the players have the same names the real players have but just one letter is different (e.g. Ronaldo is Rolnado).
Blast Corps: Fun game where your objective is to keep a truck's path clear by using different vehicles ranging from other trucks to Robots. The catch is that a) the truck you need to aide has a nuclear bomb and if it touches anything, and i do mean anything, even trees, it goes off wreaking everything and

the truck driver is the most incompetent driver ever and will always stray away from the main road to go stright to a building. This game needs the memory pack.
Turok: Dinosaur Hunter: kickass FPS for the n64, i think it was the first for the system. Some may say the sequel is better but that thing was just overflown with endless levels that took you at least a full night to get by. Basically you are turock, a native american, that gets transported to this place called the Lost Land where there are a fuckload of dinosaurs which you must kill to survive. THis game also needs the memory pack.
I'll think of a couple more games but that should suffice.