I finally got around to hacking my screen saver today - I just saw Mark Twain's ugly mug once too often and I couldn't take it any more. So when I was thinking about what to replace it with, I had a stroke of genius, and now I couldn't be happier with the results; more than 500 Sundays worth of my favorite comic ever, Calvin and Hobbes.
So what are other people doing for their screen savers? I've seen family pics and the usual "Don't Panic" that gets put by just about every geek on every device at one point or another. What else?
BTW for anyone who hasn't changed their screen saver, I highly recommend it. It's super easy.
UPDATE: Okay, once I got started, I couldn't stop. I converted all the ones that weren't showing up right so they would display in portrait mode, then I did the same for all the daily cartoons as well. Now I have more that 3500 images I'm using for screen savers - and it seems to be handling it just fine.