Since this is supposed to be portable, I want to throw in a LiPo battery, but everything runs on 3.3V. While searching for step-up/step down converters I found the pololu.com S7V8F3. I've bought one some time ago and I'll just throw it in, instead of using a booster to 5V and a 1117 to drop it down again.
Should have stayed with 5Vs, now that I'm thinking about that. Meh.