What was that about tubes?
 

So does the type of tube you use make a difference in what type of riding you do? I know about sizes and pressure but if I do only DH (I don't) would I want to have a specific type of tube that is different from the one I might want if I freestyle.

For 99% of all riding, Butyl tubes are what you want. IF you get into Road Racing then you might want to get into the lightweight, but expensive, Vinyl tubes.

Like ljbike said, a standard tube from your local LBS should do the trick for nearly every riding situation. They do make tubes that are very light(and very thin) and tubes that are heavier and beefier for the downhill crowd. These tubes are tougher and more resistant to blow-outs and other tube failures. Or you could just go tubeless, and stop your worries about tubes. As long as they hold air.