Ever since I rooted, I have been very bold in terms of ROMs. So far I've tried out Gummy, Liquid and AOKP, as well as a Franco Kernel. The first ROM that I tried out was Gummy. Gummy is a simple and very customize-able ROM. I liked how easy it was to start up and customize. I'm very glad that I chose it for my first ROM.
The next rom I used was liquid. I liked liquid more than Gummy. The only issue that I noticed was that the text box wouldn't allow me to input text at times. While it was a little annoying, it wasn't that big of a deal. Other than that small flaw, the rom was smooth and clean, and setup was simple.
Currently, I'm on AOKP. This rom seems to be flawless, and I haven't had any issues with it yet. Initial set up was a little bumpy(but not the roms fault).
If you're a beginner (like I was/am), Gummy and Liquid are excellent roms to try out until you find one that you're happy with. :)