Coldplay
I know it's uber-hip to be a fan of Coldplay, and I usually consciously avoid the smug recommendations of the uber-hip, but I made an exception for these guys. I fell in love with their sound the very first time I heard "Yellow." I don't recommend listening to entire Coldplay albums from beginning to end, unless you're on some good anti-depressants, but a nice scattering throughout your music selection is a great way to enjoy them.
Although hard to choose a favorite, I'm partial to "Shiver," from their debut release Parachutes. And it's not even all that depressing. Unless you listen to the words.