Best original Xbox game besides Halo 1/2

[Seventizz]

Wow, no one's said Crimson Skies, Midtown Madness 3, Stubbs the Zombie, Mech Assault 1-2, or PGR 2 yet?

While not technically exclusives, my picks are Rainbow Six 3 and Ghost Recon 2 which are completely different and better games than the other console versions and PC.