Thread updated. Thanks for the contris, guys. sourceninja, I had to think about it a bit, but my feeling is not to admit x servers and virtualization tools, etc., to the list. Certainly these are useful tools for developers, but it seems to me they're really operating system components and tools. If anyone disagrees sound off and we'll discuss.
By the way, I use nxserver for the same thing. Run it on my Debian Etch box and use the client on my Windows machine.