To a lesser extent, acoustic guitars are like human voices, and they get along with certan signal chains, or not. This will vary by the room, the mic placement, temperature, and humidity. The mic/pre combo that sounds good in one setting, with a certain guitar, etc., could seriously suck in another environment. Like human vocal mics, all you can do is buy cheap mics that work for somebody sometimes, and save for more expensive mics that sound good hopefully a significantly greater percentage of the time.
Start at the beginning, for jollies, with an SM57 and a good pre. That's a tutorial in the effects of mic placement. There are a bunch of ways to mic up an acoustic. There do seem to be some guitars that just sound better through a large diaphragm condenser. The majority use two SD's or one of each.
When you tire of moving that 57 around, play mix and match.
A short list of basic SD's from dirt cheap to ooh baby- Note there are several lines I'm not familiar with, such as CAD, T.H.E. ADK. My bad.:
Behringer B-5,Oktava MC012, MXL603/611, Studio Projects C-4, Rode NT5, Shure SM-81, AKG C451,Neumann , T.H.E.,Earthworks,Josephson,Shoeps, DPA (Oh my God)
LD's that somebody likes: Studio Projects B-1,Oktava MK319, MXL V67, AKG C2000B,Audio Technica 4033,Rode N-T 1/1a, NTK, (oh oh, my first tube mic).AKG414B-ULS, Shure KSM32/44. There are a bizzillion more. The competition gets fierce, here, as there are dozens of models that could be listed here in that $500-850 or so range- B.L.U.E. Baby Bottle, Neumann TLM 103, etc.. Now the entire list of badass vocal mics get into the lists of possibilities-Brauner, Soundelux, Lawson, Neumann/Gefell (a host of classic mics) Then ribbons. Many great tracks have been done with them on guitar. Royer, AEA, RCA seem popular for this. Big bucks.
There you have it. You can make good sound sometime, somewhere, with almost any combination of good mics. Instead of zeroing in on what will make a wood guitar sound good, just get some mics, at least an LD and a couple of SD's and go play. Get good, proven, versatile tools, and move them around a lot. I like 2 C-4's and/or an AKG C414, but that's just my guitar, in my room.
I wish you all good luck in the quest for that great acoustic tone. You have entered a forest with many paths.-Richie