Well, if you plan on folding, I would recommend Red Hat. That is what we use on our servers and it works very well. I have also used Kubuntu in the past as well. This interface is more Windows-like if that is what you prefer.
I would suggest that you use that Ubuntu you have available. However, if you are a new Linux user, I'd recommend you to start up with Zorin. Zorin is an OS that is based on Ubuntu but a lot easier to use and it's better for you since you can really get to know Linux.
Ok, this thread was made a month after GND started, over 2 years ago, PLEASE do not bump something this damn old, I'm supposed to give you an infraction, but I'll just give you a warning, please no more mega bumps.