Rooting question...

Is there anyway to root with 3.7 that doesn't involve losing all your data?

I'm sorry, but I don't understand what you mean by "3.7". Are you talking about the current software version? 3.70.651.1 or something else.

Is there a method in particular you are looking to use?
 
I've pretty much have had the Evo since it came out and just want to spruce it up a bit. Plus, I've read here in the forums that rooting it will can help out it's battery life and I've seen all the cool themes at XDA.