X11, the display thing used on most Linux distributions, is actually available from Apple for all versions of OS X (maybe they've dropped it, but it was there for Tiger). It's called "XQuartz" I think.
X11 has a feature called "forwarding", which allows you to run a programme on one machine and the UI on another. I don't think it will work terribly well for e.g. video, and you will get a very unmac-like user interface (the menu bar will be inside the window, for example), plus downloads will go to the remote machine. I'm not sure it'll be a good experience, but it's something you can try if you like.