for me it's the first. it feels the most fleshed out, the others seem to be a bit gimmicky or something, i dont know exactly how to articulate it but there's something about the two sequels that doesn't live up to the first.
ironically i own the two sequels, but not the first one! :lol:
Hmm, I agree with you Sterculius, the first one was my favorite. I am about half way through Thousand Year Door and it isn't the same. I am thinking it is because your partners are kinda the same (the first and second, Goombelleria (?) and Koops) as the first game. I have to say though Yoshi kicks ass.
I also prefer the first one, I played the Gamecube one for some time, but it didn't feel the same, and Super Paper Mario was nice too, but again, it didn't feel the same.