Tough, but if I had to choose I'd say:
5. Star Wars Battlefront II/I 8.8/10: great Ps2 game that I still play to this day.
4. The Legend of Zelda Franchise 9/10: Though it has had it's ups and downs I still believe these games are revolutionary in how they push the player to a mental edge that remains fun but provides a good challenge
3. Super Smash Bros. franchise 9/10: Great fun at parties, that's all I can really say for this fantastic multiplayer series
2. Battlefield franchise: The best online multiplayer I have yet to find, and with the new frostbite engine in Bad Company and 1943, this game has provided me with literally weeks of fun, and I mean accumulated play time WEEKS!!!
1. The Uncharted franchise: A set of games so beautiful in their dramatic art style and such a wonderful platforming/shooting experience that it would be a crime not to have this at the top of my top five. The multiplayer for number two has actually started to eat up my progressively smaller game time.