A couple of other choices besides the Audio Technica are the Rode and the Beheringer cardioid condensors. I got the Beheringer because of a quote about it being "the economy-priced clone of a Rode". Sorry, I'm not at home, or I'd give you it's number description.

Our group usually performs acoustically, but the few times we've used the one mic set up, it worked well. I also played with a friend's group through an AT a couple of weeks ago and it worked well also.

The Behringer is the cheapest by far, about $250 or so at Musician's Friend. However, I did buy a $50 two-input mixer board, also Behringer, because the mic needs 48 v. phantom power, which the little box supplied. So around $300, plus stand.

With one mic you don't need monitors since you're working so close. So we got away from eight mics (four vocal, four instrumental) two monitors, an eight-input mixing head, the associated stands, etc.