While the JDS desktop that currently comes with Solaris is essentially functional, I've always found it rather bland. In one sense it's a good thing - it has no major irritations (most window managers or desktop environments have something that drives me up the wall).
Still, I would like to get a bit more character out of the desktop. Unfortunately, the available themes are pretty thin on the ground. Unlike the huge array of themes that you can get for Window Maker, you're really very restricted.
I actually quite liked the new theme that the latest JDS builds come with, but it doesn't seem to be separately available.
I've found a couple of themes that I like. I've used eXPerience for most of the last year. I've got my Windows XP box set to the olive green theme, and find that color combination works quite well for me. And I've just been playing with Clear Blue, which works pretty well. It's a bit pale on my current monitor, and I might have to tone down some of the other applications I use to blend in a little better, but it's looking good.
There's still a lot of room for more gorgeous looking desktop themes, though.