Building is tempting but I've built so many I'm just burned out or lazy. Besides, back when I did most of my building, heat was just not the problem that it is now.
I havesome reservatins about Gateway but i'm under the impression that they are like Dell; their low end is crap but their high end is pretty good. I've had a lot of experience with Dell because our state contract pretty much gives us no choice. Personally I would never own anything except their XPS line which I have found much more reliable.