Live Acoustic Mic -- which one?

[Matt Brown]

Will be performing an acoustic gig coming up at a very small coffee shop. There may be a lot of people packed in, as there's going to be free coffee, and it's in a university town during finals week. I'm going to rent a mic for the occasion to record the performances, and I'm not sure what mic to rent. Price isn't really an issue. This is for recording the performance only, not broadcasting or amping it. The performance itself will be completely acoustic, no wires or amps or mics.

Any suggestions off the top of your head for a great mic that would be ideal for this situation? What type of mic would be ideal? And, perhaps, what kind of preamp would you suggest?

Here are a couple lists of rentable mics I'm browsing through:
http://www.audiorents.com/rental/14/...crophones.html
http://www.gearfordays.com/tubemics.htm

I have some experience with studio mics but have virtually no understanding of what mics are considered best for live situations, especially for what might be a loud, close quarters coffee shop environment.