Shure SM81 (for acoustic guitar)

Not a bad mic. Used everywhere for high hats, overheads, etc. One I own and recommend is the Audio-Technica AE5100, and it's about 100 dollars cheaper. If you plan to use the 81 (or most condenser mics) live for acoustic guitar it creates a feedback issue, but it sounded good.

Also consider a Chamaleon Labs TS-1. This is my fav small condenser for acoustic.

I recorded with it once... Great, great value. Its a chameleon mic. You can use it everywhere! Perfect for budget studios. BUT..For about the same price, you can get TWO rode NT5s. Maybe the NT5s don't have a pattern selection, But they are the only mics I bought after only one recording session. They are PERFECT overheads, absolutely ASTOUNDING for acoustic instruments, and are more than adequate for vocals. They are colored, more than the shure...But I really like their "brighntess". Always perfect to make something jump out of a mix. These are one buy I never, ever will regret.

I would just buy a Audio Technica 4033 and be done with it. When guys like George Massenburg claim "it is the first mic I try, and the one I use 90% of the time for recording acoustic guitar", I think you can trust it will do a pretty good job for you! ;) I was impressed with that statement mainly because I found it to be true for me too! If you don't believe me, you can find his post somewhere over at the Music Player forums. It was maybe 4 year or so ago that he posted that.

I use an SM81 through an Electro Harmonix 12AY7 pre over the fingerboard (angled towards the 12th fret) - it's a great mic/pre combination that works extremely well with a large a diaphragm pointed at the bridge (I use a Studio Projects C1 through a VTB-1 pre for that). I get extremely faithful reproduction of my Martin D-35's sound with this setup...