If you can avoid buying/owning/being responsible for the PA, do so! I find it the fact I have to cart it about the worst bit about gigging. Our set up is pretty small but life would be so much easier if I didn't have the wretched PA to deal with. Once it's yours, there's no shaking the thing off!
That said, our set up works well. Two powered [url="http://www.bluearan.co.uk/index.php?id=ALTPS4LA&seeimage=YES&img_name=PS4HA"]Alto PS4[/url] cabs and a small [url="http://www.bluearan.co.uk/index.php?id=BEHXX1204FX&browsemode=category"]Behringer[/url] mixer with FX built in. Don't forget to budget for cables (you'll need more than you think), power leads, etc etc. We each own [url="http://www.bluearan.co.uk/index.php?id=CARSS4200&browsemode=category"]Carlsbro powered monitors[/url] too which are expensive for what they are but do the job.
Edit: good quality powered cabs like the Altos or Mackies are defo the way to go for clear vocals. We A/B'd the Altos against Peavey, Wharfedale and couple of other brands and the Altos were in a different league. They sound more like hi-fi speakers.