I ended up going with one of these. I like the idea of the tank, but decided that it'd be just a bit too much of a hassle and there'd be times when I felt like painting but just wouldn't want to mess with it -- with the little compressor, I flip a switch and I'm painting. I haven't tried painting with it yet, but I did turn it on to hear how loud it is. It certainly isn't silent, but I think it is quiet enough for what I need.
Thanks for all the advice.