i would stay away from cyanogen and miui for the time being atleast, i tried both of them within the last 2 weeks and neither were stable at all for me.
if youre not ready for 2.3.x then there are a bunch of good 2.2 roms, i really liked firefly, phoenix, and serendipity. the 2.3.x roms are stable, usually on my first charge after a flash it has a battery charging problem, but after that one time it doesnt happen again, and after your first phone call after a reboot you have to run a finger over the proximity sensor to get the screen to turn back on and after that it works fine until the next reboot. those are the only 2 real problems. but while im at it if you want a 2.3.x rom then i recommend symply sgs II, which is what im on now, or mosaic