This is the best 2.1 ROM (IMO). It's built on the official 2.1 and so is as stable as they come
This is the 2.2 ROM I am using at the moment. It is more complicated to set up, since there are themes/kernels and so on to flash. It also won't have HTC Sense and any off the associated apps/widgets etc.
And yeah, the free version of ROM manager is just fine for what you'll be doing. Once you've used it to set up amon ra, as I explained above, stick the Rom.zip you want on the root of your sdcard too.
EDIT: Then you want to:
- Ensure you have all your apps backed up with TB.
- Make sure you have anything else you need backed up. Everything on the phone's internal memory is going to be wiped completely. (The sdcard is safe, of course). So contacts (if they aren't google/sim contacts) and sms messages need to be backed up, for example.
- Turn off the phone
- Boot by holding Home + Power, at which point amon ra should appear.
- Under the backup menu, do a 'nand backup'. This backs up your current firmware, so you should be doing a nand backup before you flash anything in the future.
- Under the wipe menu, do a factory reset, a cache wipe and a dalvik cache wipe.
- Then pick the option to flash a .zip from the sdcard and point it at your ROM of choice.
- Any extra .zips you need should be flashed the same way after this. (e.g. themes, kernels).
- Reboot
- Install TB and any other backup apps used from the market, restore, and have fun
