I have no experience in microphones, but from what I've seen, the Shure SM57 is whats reccomended at a basic level to everyone that is interested in instrument recordings. However, I've taken a look and the Shure PG27 may be a bit better of a choice, but I don't know much. What I'm looking for is primarily acoustic recording, but I may turn to amplifier recordings and other miscellaneous things in the future. What microphone should I look into? SM57? PG27? Something else?
you'll want to go with a condenser for acoustics. to do that though, your interface will need phantom power. make sure it has that before you get a condenser.

if you can manage 300, the Bluebird is one amazing mic (for the money). sounds excellent on acoustics and vocals. also works very well on amps a few feet back with a dynamic closer to the amp.

for the 100 range, i still the the AT2020 mic is the best (or at least one of the best) condensers out there.

honestly, i haven't seen anything impressive enough around 200 to recommend getting that over a 2020 and saving up for a better one (or a dymanic) on down the line.
Rode NT1-A if you've got the $220 for one. Its a great mic for vocals and acoustics.

The AT2020 is good (the best condenser around $100) but the Rode NT1-A is way better
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