or get a camera that comes with its own li-ion battery.

my sony DSCP1 lasts quite a while

also anytihng above a 2MP will be fine, thats takes pictures that will be hi-uality up to about A3 size so i think thats good enuf people just upping and upping the specs to get people to buy them, but TBH they're well overspecced for 99% of the population