$849 gets you an Alienware Alpha. I recently got one, and they are great, but a couple issues that you might want to consider
Pros:
Small size, for those of us whom are ancient gamers have seen the wonder of the Nintendo Gamecube, Alpha is a little bit bigger than that. It's amazing really.
Intel Core I7 with 8GB of Ram, plus its easily upgradeable
NVIDIA 860M GPU with 2GB GDDR5
1TB HDD space for all you're stuff
Is a hybird machine, it can be both a gaming PC, and a gaming console with Steam
Comes with XBOX360 Controller and software already installed on it
Hooks to your TV really easily.
Cons:
GPU is not upgradable.
It's HDMI Only, meaning unless you got a HDMI compatible monitor, then Alpha is only going to run on your TV, unless you're TV is only 480P
For speakers, well, since it was really designed for running on TV, it doesn't have a typical 3.5mm audio jack like most desktops, you need USB speakers or headsets
For some, Steam being pre-installed on it might be a con, but it wasn't for me.
No CD drive, meaning that it does downloads only, and there's nothing in it for CD's.
Only 4 USB ports on the whole machine.
Other than that, it is a great machine.
