Really there aren't any BEST roms. It's just try and see what works best for you. Some people might have a rom that they say is wonderful, and then you get it and get FC's, or something doesn't work, or random reboots. I am loving MIUI. Like CM7, have to toggle wifi on a few times, and download Moboplayer, or some equivalent, for movies, but all in all it's wonderful, and very customizable, which is making me very happy. I change themes about 5 times a day, because I'm at work with nothing to do.
It's just trial and error. Try MIUI, CM7, RandomRom Thunderhawk, and there was a red era eho6 one that was pretty nice, too. I think a lot of the roms with the lockscreen mod tend to do like a soft reboot. It'll be on lockscreen, go black, and then pop up like it was just turned on. At least for me it does it.