Eight years ago, I wrote this for the rec.audio.pro FAQ; it's still pretty valid:
This is really an unanswerable question. Go to a local studio with a good stock of mics. Buy a few hours of studio time. Ask them to record your voice using the following mics through a pop filter. Sing about one minute of the same song, but don't identify which mic your using on the track. Have the engineer keep track of each mic and which track it is. DO NOT LOOK AT THE TRACK SHEET. Mics to consider:
Rode's
Audio Technica's
AKG's
Shure SM-7
Sennheiser 421
Neumann TLM-103
Any Beyer ribbon mic
Shure SM-57
Any other mics they have in the below $1,000 price range (MXL, SP, Nady, etc.).
(If they have a U87, or other expensive mics, get recordings of those too, as a reference.)
Have a CD-R made. Go home, hide the track sheet, and listen to all the tracks for a week. Pick the tracks you thinks sounds best and write down the track numbers, then put the CD-R away for a week. DO NOT LOOK TO SEE WHICH MIC IT IS !
After a week,listen to it again and see if you still like the same tracks. If you choose different tracks, put the CD-R away for another week.
After a week, listen to it again and see if you still like the same tracks. When you pick the same tracks twice, a week apart, those are the mics for you. Get the track sheet and find out which mic they are. No cheating, and you can have other people choose as well.