To move from XP onward, no need for State of the Art, just so you know, Vista is plentiful, improved AND supported for some years to come.
I got Windows 7 a plenty now, oddly, was longing to own the OS for a number of years, then the discs started showing up as I took in project PCs, I even scored an Acer Vista Home Premium restore disc set from eBay.
I built up an Asus ROG laptop as a budget buster project, I wound up getting a GTX460 nVidia card for that, not far from your specs, I don't have Ivy Bridge, Sandy, or Haswell yet, but the main advance has been socket 1150 Intel, Haswell IIRC, Was supposed to be augmented by one last 22nm CPU. [Broadwell was delayed for some say, lack of competition from AMD, just as ATI and nVidia aren't in direct competition]
Some years ago ATI/AMD said they'd give up competing with Intel, at least officially, but they still make CPUs and GPUs.
For a system with gaming intent, desktop, might want to invest long term in SLI or Crossfire, up to 4 cards in unison, but you give up most all other card slots in doing so! It also is marginal performance since it's sharing graphical rendering duties at any given time. Desktops can expand much more, as we've all noted before, more user upgrade components, but for Windows 8, I'd go nearly strictly with a touchscreen laptop.
SSD can speed up any computer, but the sad end is RAM is becoming expensive no matter what type you're after! It's uber costly to go all out with the best RAM you can buy.
Thankfully we can edit these up to 24 hours at least, I figured a newer response since mine, but I thought I'd aid any Intel shoppers out there, since curiosity hit me as well, might wanna hold out for the end of this year, according to this.....