I support Cloud/Aeris. Without getting into heavy details, there was simply more chemistry between the two. And yes, now she is dead, so Cloud should pick someone else... I don't think Cloud/Tifa is a good match though.

But all in all, one of things that truly made the game great was how the player can decide. Depending on who you are nice to, you can change the Golden Saucer date by having it with Yuffie, Aeris or Tifa...and... ... ... Barret (but there is no homosexual stuff, it's like an outing with two friends...not a date).