Wait, this is actually more interesting than it sounds!
A few days ago, I was messing around with my LiveJournal page settings, trying to come up with an attractive and readable combination of text and background color. I wound up typing things like #FF80BB (i.e., the RGB codes for HTML colors)again and again, and reloading my page, just to see how it looked...
Wish I'd known about this:
IDEO Web Color Visualizer
Try it out, it's very cool. Doesn't cover all possible colors, of course, but lets you get an idea of the effect of a lot of combinations, and makes it easier for you to tweak on your own.
BTW, this was an entry last year in an odd-ball contest for the most interesting web page in less than 5K bytes. Last year's winners are here: 5k.org winners, and the current contest entries for the 2001 contest are here: 2001 5K.org entries. Most aren't that great -- Sturgeon's Law -- but some are very cool.