I just downloaded http://linus.differnet.com/experience/atlarge/klee-highway.htm for my 22" monitor and http://linus.differnet.com/experience/atlarge/klee_parnassum.htm for the 17 incher. I like them so much I don’t want to cover the screen with ugly stuff, like work 
I use Webshots and change my wallpaper all the time
My wallpaper is the cover of my current favorite band, Millencolin’s single “Fox”.
Now that you made me look, I’m now trying to decide between the other two here:
http://millencolin.com/free/flaming_logo.jpg
http://millencolin.com/free/penguins_cover.jpg
I have a whole bunch of Fillmore West concert posters that I rotate as wallpaper. I usually change it everyday.
I use pictures I take while on vaction. I change them often.
Currently I have a picture of the Trevi Fountain.
I am dying to go back to Rome.
Currently, it’s a picture of the county courthouse in Sulfur Springs, TX, which looks like an old castle. It changes weekly on a whim as I play with my digital camera, though.
DW, Whereja get those? I’d like to checkem out.
As for my wallpaper? Well, duh, it’s Speed Racer! It’s the opening sequence shot of him jumping out of the Mach 5 in such a way that instead of looking cool, he looks all contorted and whatnot. But with the ascot and brown loafers, what’s not to like?
At work I have a screenshot of a GM character from EQ that was created in my honour. Before that I had a scanned pic of me and Mr Mauv (yeah I know).
At home I change it quite often. Lately I’ve been rotating between these:
http://www.alice.ea.com/images/wall5_800.jpg
http://www.alice.ea.com/images/wall4_800.jpg
http://www.alice.ea.com/images/wall3_800.jpg
http://www.alice.ea.com/images/wall1_800.jpg
I typically flip between images I’ve created via Terragen. Currently using this one:
http://www.inil.com/users/edamoth/Terragen/costa.jpg
I actually have a pic that chef troy took a long time ago…maybe 6months?..It’s a beautiful black and white photo of a bridge. I’m going to be sorry to leave, because I can’t take it with me.
Home: Beige G3 Mac: Celtic cross design
Work: iMac: painting of Yoda using an iMac
I sometimes use kaleidoscope as part of my gui
HST image of the Orion Nebula with the colors punched up a little. It actually looks pretty abstract, and not necessarily like an astronomical object.
As if anything else belonged there. The Tick.
Last one was a diagram of cuts of meat.
Comp at Home: Stormy Ocean Shot
Comp at Work: Hawaiian Sea Slug via The Slug Site…changes weekly
No wallpaper. Completely black background.
Before that it was an arrangement I made of professional pics of my then-girlfriend. That had to go, obviously.
Before that, it was a 3d rendered picture I made of an angelfish in a torus of water in front of a doom-style computer panel.
Right now it’s just a boring green/black gradient thing. Before, I had a cool image from the game “Terminal Velocity.” My backgrounds are typically dark/black.
On my other computer I have a bunch of images that I randomly generated using a computer program I wrote. I could upload them so you could all see, they look very cool (but at the same time, they don’t totally distract you from the desktop images.)
What I want to do (if it is possible) is to make a Java program that is a moving starfield of some sort, embed it into an HTM file, then do that “use webpage as background” effect that is in Win98. If it works (it probably doesn’t. :() then it would kick ass.
(Note: I don’t even really know Java, but I know C++, so Java shouldn’t be that hard to learn.)
Joph: I’m not sure what Terragen is, but that is simply beautiful.
Unfortunately, the Fillmore S.F. site…
http://thefillmore.com/
has changed their look since last I visited. They used to have a real nice layout, where you could just click on a year and scroll through all of their posters.
I do have a few other sites where you can find poster images:
http://www.artrock.com/cgi-bin/hazel.cgi
http://store.yahoo.com/sfxc/bghome2.html
http://blazer-usa.com/shopsite_sc/store/html/page6.html
Also, if you search around for “fillmore art”, “fillmore posters”, etc., you can find more.
p.s. - If you’re looking for any Grateful Dead posters, you can find a bunch at http://mars.dead.net
Hopper’s Chop Suey. At this time, I believe he is my favorite American painter.