I won't actually register a vote here, because there is no best rom. This weeks best is next weeks also ran. Its amazing the amount of development going on at the moment. Very cool!
I would put a negative vote against tkcROM if I could, not because its crap, which it isn't, but just because it isn't actively developed any more.
When I had my 5500, OZ was by far and away the best rom I tried on it. But things may have changed since then.
On the c7x0, Cacko 1.22 lite or pdaxrom are the ones I have most experience of. I'm currently using pdaxrom, only because I got bored of the qtopia user interface. I like the customisability of X. I looked at GPE, but I wasn't sure which, if any, applications would work on there outside of those supplied in the feed.
After quite a short period of experimentation, it was clear that I could do everything on pdaxrom that I was doing with my Z using Cacko 1.22 lite. So that's my day to day rom at the moment and I'm happy as the proverbial pig in sh**.
By the way, should you not list Watapon on there?
Mike.