The only couple out of your five I like are Jack & Kate. I don't like Lucas/Peyton and I've never even watched the other shows.
I think I'm changing my #5 to Peter/Olivia. I can't believe I forgot about them!
So...
1. Vaughn/Sydney (Alias)
2. Nathan/Haley (One Tree Hill)
3. Jack/Kate (Lost)
4. Clark/Lois (Smallville)
5. Peter/Olivia (Fringe)
3/5 of those are JJ Abrams shows.