Building a new computer

[KillahPriest]

My current computer is real slow so I was looking to upgrade it. I primarily work in 3D apps (Maya, Zbrush) and wanted to know what I should look for. I know the most important things are the CPU and RAM, but then I need a new motherboard - I don't know too much about building computers.

Would I be better off buying a premade one? Or does anyone have recommendations on where to get started?

This is what I have currently.
http://www.newegg.com/Product/Product.aspx?Item=N82E16883113055

[KillahPriest]

I was looking into premade comps but I shopped around and found I could get a better deal if I did it myself.

I heard the graphics card didn't have much to do with Zbrush or Maya and that it was more CPU and RAM.

[CompanionCube]

Maya uses the graphics card, zbrush doesn't