I would give the CM9 nightly a shot there was a new one released on the 30th March it's actually amazing, As the above post says though after one you will end up doing another and another, its a bug
If you need any help or get any issues give me a shout.
been looking at ROM for my desire and basically there seem to be three main options are
- Modded stock ROM so basically a modified version of the one for your phone (or sister phones)
- AOSP (Android Open Source Project). These are built of the base android O/S and don't include any extras that your phone manufacture put on like touchwiz or sense. CyanogenMod is based on this.
- MIUI Chinese developed ROM based on CyanogenMod 7 that is supposed to resemble iphone. i haven't loaded it myself but its supposed to be very customisable
Of course there are hundreds of ROMs out there but they seem to be grouped on the above