I recently heard about Nginx. It's a web server with a great track record in Russia that's starting to spread out to the rest of the world. According to a recent podcast I heard, Zed seems to be using it with his production Rails apps, which is always a good sign. At RailsConf I got to eat with Adam Keys and his enthusiasm for it's speed, ease of configuration, and stability caught my attention.
The greatest attraction for me is the ease of configuration. I've wrestled with Apache conf files on and off though the years, but I've never felt like I really "got it". Apache can do nearly anything, but you've got to really invest the time to become an Apache specialist to do anything useful with it. And I never really felt the motivation to become an Apache specialist.