Although put together in 2011, this is still my current PC setup and can play games like Skyrim on high, Deus Ex:HR on full, Hitman Absolution on full, and generally handles most things I throw at it. **Update: Can also play Metal Gear Solid - Ground Zeroes on almost full everything with the exception of the topmost shadows and effects, averaging between 40-60fps.
Cost approximately £800 GBP or $1,250 CAD at time of build (2011).
Updates to this build can be found here: https://ca.pcpartpicker.com/b/3nnH99
Very capable Intel CPU easily overclocked to 3.07MHz, theoretically overclockable to 4 MHz and beyond with the right setup (which I don't have....yet).
The Antec Kuhler 620 water cooler honestly doesn't seem anything special, with temps idling around 50C on stock clock. Was previously OC'd to 3.5MHz, but idle temps were too high for my liking, around 60C, and load temps hitting the 70's.
I actually have the Sapphire Radeon 5850 Xtreme version. It's a great base card, but a little disappointing in the overclocking department. Don't know why, but it just won't hold a single stable overclock, even just using ATi overdrive will cause things like Skyrim to crash. Bit puzzled as to why this is, maybe I am doing something wrong as other people have managed to boost this thing quite a bit.
The Fractal Design Define R3 case is very nice, spacious inside without being massive on the outside. Plenty of places for 120mm fans. Almost too much room for HDDs, and in newer versions of this case half of them are removable.
My Corsair 450W has never failed me, even if it's only 450W I have yet to need more than that. Only downside is that it is not modular and you end up with a bunch of unnecessary cables to try and hide.