How I think they should be:

Irvine+Rinoa
She seems really boycrazy to me and like she'd put out for any guy who'd date her, and that would work out just dandy for Irvine's crazy hormones!

Selphie+Laguna
Selphie likes him. And he's a nice guy. With pretty hair and a gun. I think they'd be really cute together. Even if Laguna is kind of old for her.

Squall+Quistis
I would have said Squall+Zell but that definitely would not work out cus he's so whiny and when they break up he'd go cry to his mommy. Squall+Quistis=hott!!! She's not as needy and demanding as Rinoa so he doesn't have to save her all the time.

Seifer+Zell
this one is a joke but I think it would be funny. lol
Zell: "Aww man, they're all out of hot dogs again."
Seifer: "That's okay, you can have MY hot dog."