This site has a great writeup/comparison of the various VPS (virtual private server) hosting plans available. Quite interesting. I believe that this type of hosting will become more popular versus racking and hosting your own machine. The economics and flexibility are just so much better.
Note, if you use Interland, they advertise a VPS type server, but it is not the same. They are just using the FreeBSD jail mechanism to let you think that you are using a VPS. Still, that might be fine for some of your needs.