I would probably say Bugless Beast. Mind you I have yet to try it on my wife's Droid Incredible. However I have used Bugless Beast on the OG droid for as long as I have had the phone. Peter Alfonso just released it Saturday and I just found out about it this morning. It is an AOSP ROM and therefore has none of the flash that you would get from things like Sense. Only catch is the camcorder doesnt work (that is the only known issue right now on the Incredible). He just started ROM'ing the Inc as of recently so there may be bugs. However all of his other releases are top notch.
I have always installed ROMs manually. I haven't been ROMing for very long though. Still, I have seen people talk about the only thing they would use ROM Manager for would be to udpate recovery and maybe, maybe, just maybe, run a backup, although, they don't trust doing even that with it for some reason. :blink:
CM7.1 is good, I used it for a while on my Droid, I have been using it on my Nook Color for a while too (well maybe not the .1, but cm7)... That being said, I primarily install the roms manually on my Droid and Incredible.. the Nook Color though I always have a hell of a time getting into the recovery so I just use ROM Manager and I have never had a problem. I suppose it is just what you feel more comfortable with.