Just built a system using the X-QPack (all black, no windows). I'm very happy with it.
Used an MSI K8NGM2-FID mobo, A64 x2 4800+ cooled with a Zalman CNPS-7000CU, which fits no problem. I went with an eVGA 7800GT, also no problem fitting it in. The slide out tray makes installing things very easy. There have been some complaints about the stock 120mm case fan being noisy, so I went ahead and replaced it with a Thermaltake A2018.
I replaced the stock PSU with an Enermax Noisetaker 485W PSU. It was a little tight fit with the Plextor 716SA DVD - the back of the SATA data cable is pretty tight against the PSU but it does fit. Just make sure your DVD is no more than 170mm long and you'll be ok. Some poeple are using the Enermax Liberty.
If you haven't already heard, this case is not the most "polished" case out there - its not a Lian-Li or Silverstone by any means, but it does well for the price. There have been some complaints that its a little "flimsy", which are true, but once you get components in it, it feels pretty solid.
Lots of users have reported problems with the unit shutting off spontaneously, shutting off if its bumped (or tapped) or not powering up at all. I myself suffered from the not powering up problem. All of these (from what I have read and my own experience) have been caused by the power switch shorting out against the frame. There is one unused, uninsulated pin on the back of the power switch that rubs against the frame. Its very easy to fix - simply remove 2 screws, unlatch the front cover from the front of the frame, pull front cover off a little bit to gain access to the back of the switch, bend unused pin foward (I added a small piece of electrical tape to the entire backside of the switch for good measure) and reassemble. Problem fixed.
Like I said in the begining, I'm very happy with this build. I'm not a hard core gamer, so I'm happy with the single 7800GT. From what little I know so far, if you want an SLI rig and can find a mATX mobo that supports it, this case would be ok as long as you're not looking for expansion on the PCI bus, as the dual PCI-E may eat up all the available expansion slots at the back of the case.
Hope this helps. Good luck.