It depends. I really just enjoy good games but it seems Nintendo seems to make the best games. I therefore reserve most of my money for those excellent 1rst party titles. Now it doesn't mean I don't buy third party games. I currently own the following third party games:
Beach Spikers
Dr. Muto
FIFA Soccer 2002 Major League Soccer
Hunter: The Reckoning (It was 5 bucks ok? and yes the game sucks!)
Mortal Kombat: Deadly Alliance
NASCAR Thunder 2003
NFL Blitz 20-02
Resident Evil
SSX Tricky
Star Wars Rogue Squadron II: Rogue Leader
Super Monkey Ball 2
The next three games I plan to get are also third party:
Burnout 2
Splinter Cell
Hitman 2 (depends on the controls...)
First Party I Have:
Animal Crossing
Eternal Darkness: Sanity's Requiem
Legend of Zelda: Ocarina of Time / Master Quest
Legend of Zelda: The Wind Waker
Metroid Prime
Star Fox Adventures
Super Mario Sunshine
Super Smash Bros. Melee
Wave Race: Blue Storm
It is no surprise though that my fav games on the GC so far are MOSTLY Nintendo developed/published games
(in order)
Eternal Darkness: Sanity's Requiem
Animal Crossing
Super Mario Sunshine
Metroid Prime
Mortal Kombat: Deadly Alliance
And the reason Zelda is not up there yet is because I've only played it 2 hours so far