I'm using a Common Sense RC 1250 LiPo and an EFlite 3 cell balance charger.
[link=http://www.commonsenserc.com/product_info.php?cPath=37_31&products_id=45]Common Sense RC Battery[/link]

This battery seems to work well. The LHS told me that they (Common Sense RC) are better to deal with than EFlite, and the same capacity battery is cheaper, and works about the same.

I can tell you that my motor heats up long before the battery loses power. Does anyone else have that problem with the standard brushed motor and LiPo's? It seems that I lose head speed, but the battery is cool to the touch, and measures close to 11 volts, but the motor is hot to the touch....I thought I saw a thread somewhere here that talked about venting the motor better?

OK...found it!
[link=http://www.rcuniverse.com/forum/m_5548099/anchors_5548099/mpage_1/key_Heat%252CSink/anchor/tm.htm#5548099]Got LiPo thread[/link]