Hi Amy, Lets see if I can confuse you a little more. All good and valuable info above.... so well worth considering. I'm thinking I'm a lot like you, kind of a minimalist who really likes the tone and sound of the instrument you own. For my money, and I have installed a few of these with good results, K&K under bridge pickups are it. Doesn't change the sound of the guitar, are fairly inexpensive, totally passive (no battery to change or have stuck inside the guitar), fairly easy to remove without leaving holes or other evidence.
Basically three little microphones mounted underneath the bridge that transport the vibrations out to whatever amp/effects hardware en-route to the PA. No dials no twiddling or fiddling, everything happens at the mixer unless you insert something in the chain.
As for a vocal mic, you will want to try as many as you can (the same for your guitar for that matter). Brands and models will vary in frequency response and be stronger in some frequency ranges (a good thing if you need a little push in some areas and less in others). A good vocal mic that fits your voice can really let you get the best you have out there and even out the rough spots. Some filtering is done at the soundboard, but you have some control of what gets there by having a personal mic.
Either way, it sounds like a fun way to spend your shopping weekend!