Xbox. and Gamecube,
Morrowind made me buy the console cause i couldnt afford PC to play it. but it also had alot of awesome exclusives. I did buy all Gamecubes i wanted later on and play them on my Wii now.
But Xbox had some very unique exclusive games.
1) Morrowind
2) Phantom Dust
3) Yager
4) Breakdown
5) Kingdom Under Fire series
6) Panzer Dragoon
7) Halo Series (Halo 2 i played the most in college)
Conker
9) Crimson Sea
10) Old Knight Republic Series
11) Jade Empire
That just to name few. Very different very Exclusive Games, You couldnt find anywere else.
Gamecube did have also game as well
1) Paper Mario
2) Twilight princess Zelda and Windwaker
3) Mario Kart
4) Lost Kingdoms
5) Fire Emblem
6) Luigi's Mansion
7) Tales of Symphonia
Baten Kaitos series
9) Eternal Darkness
10) Pikmin
11) Skies of Arcadia
Both Great Console but both different depending on style or preference of games. But i got to say Xbox is my choice. Because Gamecube was lacking of games. On Gamecube total is maybe 25-30 games i wanted. On Xbox it became 50-100. Their was far less good of selections other than the games i listed for Gamecube.