NPR had listeners submit lists of their favorite SF titles! Here it is (http://jillbertini.livejournal.com/836944.html).

It's funny, because another friend of mine just posted basically the same question on FB - can you name a literary (I guess that means non-genre) novel from the last 3 decades that isn't sad or depressing? I couldn't think of any. and that's why I don't care to read them, either!

I love SF and historical fiction and then all variety of YA, although that skews toward fantasy, too :P.