Oskar Kokoschka, Edward Hopper, Edward Munch, Egon Schiele, Francis Bacon, mostly expressionists.
I'm kind of an art exhibition geek. It's always stunningly different if you see the actual painting in front of you.
Like The Scream that was stolen a few years back. Absolutely tragic.
I think the one stolen in 2004 has been recovered. I remember that when I first heard about it, I was glad that I saw it in it's last exhibition before the theft (might have been the last chance). Fortunally it's back now.