I adored the love story in War for the Oaks by Emma Bull. There was nothing complex about it, but it left me happy.
Then there's the childhood crush/best-friend love story in Bridge to Taribithia, a book I have never forgotten.
I was also fond of the love story in Stephen King's Bag of Bones, both the developing romance with the single mother, as well as the saying-good-bye love he's dealing with, with his dead wife.
And finally, and I don't care what you think, I still am made happy by the love story between Kitty Pryde and Colossus in the X-Men comics (witness Astonishing X-Men, where it's perfect)
EDIT: Sigh. All that writing, and then I realize you put up a POLL. Hmph.