I think alot of software gets overlooked because its potential isn't obvious, but one software I found that I'm sure I'll like is Fractor3. Fractor3 is created by DeviantArt's own :TheShenR:, who has a small gallery, but it is definitely revealing, at least in my opinion, about the capabilities of the little program.
For example, you might think the following was from UltraFractal:
Not bad, right? It was made with Fractor3.
Other samples that might be of interest hinting at the ability of this program:
LinksFractal forums information page link
Direct download link
(includes launchers for Windows and Linux in the .zip)
And, of course, I had to toy with it as well.
To save you alittle time figuring out coloring:
Go to the menu panel and click Options->Filter manager. Click the Escape time filter. Set its color density to 100 and select the "Smooth (mandelbrot type)" checkbox.
I'm under the impression that the program needs a little more "love", or at least some attention. I'd like to see people try it out. Please post your results in the comments. Thanks!