I've been keeping a close eye on the latest batch of "smart" watches - the Pebble looks to be the best of the bunch, but it looks awful bulky and the implementation hacky. So far, I'm not impressed.
A curved or flexible screen could provide enough real-estate for touch UI while also minimising bulk.
I haven't worn a watch in at least 10 years, but a slim, functional, iOS-compatible watch could change that.