Regarding SD cards and draining batteries--I think that the type of SD card may make a difference. When I put a micro SD card in my cell phone, the battery drained noticeably faster. I swapped out SD cards with another brand and haven't had a problem since.
I've not experimented with my Reader. I've had a 2gb Kingston card in there, with only a few things on it and don't notice much of a difference in battery life.
dordale