I love Sydney&Vaughn being together all the way but I have to pick Irina&Jack, I adore them... and Jack didn't get married in 9 months after the supposedly death of Irina..
Syd and Vaughn!!! no contest, the best couple.
They are the ultimate couple of the show. Any scene where they are interacting is great.
But, i have to say that perhaps the CUTEST couple is Wadia. The visor/icecream thing, cute.
I think Sydney and Vaughn is a good one, but the cutest is Nadia and Weiss, as short as their relationship is. They are so cute together, especially her birthday party and the "tall, dark and handsome" bit