When buying a new computer I usually just pick one that seems CLOSE to what I need, and worry about upgrading later. However, the last few generations of computers, even fullish towers, are difficult to fit GOOD parts into. I've had good luck with Dells over the years, I'm on my 3rd and its 8 years old. However, looking around Dells site I've come to realize the customization is just not there anymore. I can choose between AMD and INTEL, but BOTH have built in GFX cards, and BOTH have CRAPPY PSU's which means BOTH those parts will need to be upgraded right out of the box. All this is a longwinded way of me asking this question:
Does anyone have any suggestions on a good Gaming computer that's around $1000.00 ( that's MAX end, would prefer $750-$800) that can either A) be easily upgraded or

Also CPU is a bit of a conundrum also. My current PC runs an AMD Athlon II Quadcore and I have to say I've been pretty damn happy with it. But I also been reading that the Intel I7 blows the newest AMD chips oughta the water. The I7 is also significantly more $.
So I'm back to square one: Dell, Lenovo, Asus, or somebody else. I'd rather not build my own because I don't have the patience.
Any advice would be great.