One Day. It wasn't bad but I don't really see what the fuss was all about - Dexter doesn't deserve Emma, he's a spoilt, selfish, rich kid, with not too many redeeming qualities. I kept on thinking "what does she see in him?". And the ending was (spoiler alert) a bit like Cold Feet, not very original. Don't get me wrong, I loved Cold Feet. But that's a few years ago.
Aha! I just read that the author, David Nicholls, used to write for Cold Feet. So that explains it all!