Squall and Rinoa... oh wait a minute.
Seriously speaking, though, if we're not including couples of the same gender or couples of different species, I'd say Selphie and Raijin. Selphie's quite cheerful, and Raijin is a brute.
SELPHIE: "Train, train, take us away..."
RAIJIN: "Hey Selphie, I like you, ya know!?"