Blue Bookmarks... pictures

Little Worlds - Rebecca Stewart's glass paperweight sculptures
The Plugin Head - A useful site of Photoshop resources and art.
POV-Ray's Hall of Fame - a collection of cool rendered images. Unfortunately, the page is no longer supported by the POV-Ray Team but at least it still exists.
Steve Jackson Games: In Nomine - Cool professional comicbook style art for a dark demonic game.
The original(?) photo of some really nice waterfalls (jpg image, 247k) comes from this directory. Warning, the directory is huge and though there's a lot of other images there, it does NOT seem to be a collection of scenic photos. There's a faster loading detail of that image here (jpg image, 27k).
There's an engineer at a little techie school on the east coast with an eye for cinematic moments and this ability to catch them on film.

Insects and Angels - A really well done ezine full of sepia tones and somewhat seductive collage art (slow connections not recommended)
Windy's Free backgrounds and buttons Well organized, good original stuff. Some of the categories are just color changed versions of the same thing. Some are made from original photos and other peoples' art (with permission of course).
Oakchase is made by a person who used to be known on the web as "The Lady" Diana Dru. Now (9906.24) known as "The Lady Melody" or some such. She has a nice collection of mandelas and other radially symmetric art. Some of them were turned into backgrounds. Some even have matching buttons. She also does the bryce thing a lot.
Moyra's Web Jewels - A popular site for background sets for a link, excellent attention to detail/html (slow connections not recommended)