I really don't know what new, pre-fab systems go for, (they range from a few hundred to an easy thousand, or better), not very appealing to me considering what you get out of them, no where near as high of quality as custom made systems.

I paid almost $500 for all the parts to a "top of the line" gaming center system.
My dot does quite a bit of movie making, gaming, several messengers running and videos. I wanted to make something for her where she could do that simultaneously without lag, and where I can upgrade later when the time comes. I did just that.

If I were to buy a pre-fab system of the quality that I built, then it would have easily run a couple thousand. Gotta keep in mind though, most store bought (pre-fab) cannot be upgraded much. Can add maybe another gig of memory, (if the motherboard accommodates with extra slot).
With a custom built, you can choose a motherboard that offers 4 extra slots for memory, (as well as what's already onboard),and an extra slot for a second video card. As well as a quad core processor...oooohhhh, so sweet.

My system is a hand-me-down with only room for a second memory slot, which I've already filled. I've replaced the video card already, but because my system's already so old (about 5 years), everything on it is obsolete already and they don't offer upgrades anymore...so if, no, WHEN it crashes, (and it's getting there..lol), I can't buy anything to fixie it....it'll be on its way to computer heaven.

My turn for a great one is next....yay.
Taking a system in to be fixed runs into the hundreds.
(This was an idea that Kristian and I have seriously considered to begin as an in-home business (once he gets here). Between the both of us, we were intending to start a custom order/build computer shop and a web site design service.
We work very well together..sigh....(someday).....

Shangrala