I like AA cells. You can get a set of four 2100mAh NiMHs for about £6 - much cheaper than any replacement LIon battery. And you can use disposables if necessary. It uses Compact Flash cards too which are cheap and versatile.
BUT, it seems to be manufactured in Taiwan by
J-Link. There seems to be limited support. I think I would stick to an established camera maker. Have you looked at the Canon A70 - it's only a little more expensive?