Hi,

Consider how large the venues you will play at first and foremost. When you move to small venues in the future, consider that. I would recommend a small PA myself as they are designed to "throw" a certain distance and amps are intended more as monitor sources onstage. However, if your small venues are places that will only hold about 30 to 50 people or you'll only play larger places once every six months, an amp may be a better solution since it is easier to carry around rather than a PA. For the very few times you need a bigger system, simply rent and charge a little extra so you get back the rental fee. If you're looking at venues of 100 or more people than I would definitely go with a small PA.

HTH
Fernando