For batteries, I've recently switched from 270 mah Nicds to 720 mah Nimhs. The size of the pack is about the same, but quite a bit more juice. I have tried a couple 6v packs in my quickees, but didn't notice much of a difference. I've pretty much stuck with 4.8.

I get the packs at www.radicalrc.com at a very good price.

On the 270 mah packs, I felt comfortable at 8 flights of 3 minutes, or roughly 25-30 minutes.

On the 720 packs, I feel comfortable up to an hour of air time.

Depending on your plane and setup, your mileage may vary. Do some testing of your batteries early so you can feel comfortable with your flight times.