I used to be down on poor ol' X Windows. I bought into the hype that it was slow because of the "useless" server / client method of message passing. Well, after a few minor tweaks (like turning vertical sync off, which nvidia had somehow turned on by default...) X Windows (running the latest xfce, on Slackware) is flying.
So I thought I'd fool around.
First it was xnest. Then xnest inside xnest, inside xnest, and so on, until I had twm sessions inside fluxbox inside windowlab inside xfce. Quiet interesting and fun to see.
Alright, let's try forwarding over ssh. Of course it works flawlessly to a remote Linux host (my laptop). Let's try Windows...a little tweak here and there with putty and cygwin, and we are off to the races.
Now...my friend's Mac. Hmm, start up xterm (through X11.app I think), ssh -XY, and suddenly they have the full selection of Linux programs working remotely. Gimp, open office, xchat, all going great.
Just thought I'd share. On a single system, X Windows is...good. It does it's basic job, and matches the Windows explorer.exe shell for speed (in my case at least). But when you start to open the door to it's true use, that's when you see the power. Great stuff.

Hey, that's pretty sweet. Care to share how you went about tweaking it? (Both the commands, and which opeions you chose)