What class SD card do I need?

I just bought a Nikon D3100, and I need an SD card. I was going to get one from amazon, but saw different classes of them. What class would I need? I'm so confused.

10 if you're recording video. It's not so critical for photos.

Well, the higher the number, the faster the card. I wouldn't recommend a Class 2, but you might work with a Class 4 or Class 6 if you aren't planning on taking video. If you are, then a Class 10 would be what I'd recommend.

For images only class 6 is enough but if you wan full hd video then class 10 is required

With the price of class 10 cards being so low, there's really no reason to get anything else.

Like this one:

http://www.amazon.com/...0037FLUYU/

16GB, class 10, $28.