We bought that exact camcorder about 6 months ago and I spent an inordinate amount of time trying to figure out how much memory to add and what size battery to get. I finally ended up getting the 32Gb card because I didn't want to bother with downloading the card more frequently. I have used the 8Gb card it came with on a few occasions and that one's annoying bc I think it only takes about 1 hr worth of video on the better video quality setting.
Re the battery, the charge on the standard one doesn't last very long at all. Again, it was cutting out much too early for our preference. So I upgraded to the largest one I think and have been totally happy with that. Note that the larger batteries are actually larger in size as well, which means they stick off the end of the videocamera. I wasn't expecting that. It's not a problem, just something worth mentioning.
Btw, I am very technically proficient and I found the video downloading instructions VERY confusing to follow. I never had any issues with my old tape-using camcorder, but with this one I had a hard time following the instructions. I finally created a short, bullet-pointed cheat sheet for myself that I now follow everytime. If you want me to email it to you just PM me your email addy and I'll send it over.