The camera is limited to SDHC cards, so no extreme stuff such as 128gb SDXC cards.
With this in mind, I had 16gb SDHC cards on hand so I'm using that. I film in 1080p and that takes a lot of space. (What you see in the video isn't real 1080p though, the video is zoomed, it's a wide angle camera. I just bought a new 4.35mm lens, just gotta wait for it to arrive.)
It's about 1gb per 10 minutes which gives me about 2.5 hours, output is a .mov format file, all settings set to top quality. It's easy to bring this down if needed though. I could go as high as 6-7 hours if needed. Use a 32gb card instead and that goes to 12-14 hours.
After editing audio and stuff, the end size was about 5gb, for some reason Windows Movie Maker likes to tack an extra gb on my videos. I should look into this, there are definitively big improvements that can be made in the filming and editing department of my videos. There are also probably more size-friendly file formats that I could use.
YouTube didn't seem to have a problem with me uploading a 5gb file.
Also, I don't really know about the battery life of the camera, I'm always plugged in with a 15ft USB cable to a wall adapter, but it does seem relatively bad. The display must be using a lot of power. Keep in mind that even GoPros have relatively short battery life, 2ish hours I think.