Since I haven't completed watching all Gundams, as of now, I voted Gundam Seed because it was the first Gundam show that definitely attracted my attention. However, if I haven't watched the Gundam Seed, I will choose Gundam Wing. I like those battle scenes, graphics, mobile suits, music and the characters development. Trowa is the one I like the most and then the kindest with a bit psycho mid-Eastern prince (can't remember his name). Unfortunately, Gundam Wing does not have so much romance as in the Gundam Seed. Heero never kisses Relena.
The story of Gundam Wing had been constantly shifting that confused me which side was actually the enemy.