Honestly, for the cost, I wouldn't build. Big OEMs get a break on Windows that you don't. What I would do is find a good standard ATX mini-tower, with PCI-e expansion, that has at least an Core i3-2100, 6-8GB of RAM, but no video card.
Intel's CPUs are far faster than AMD's, today, and most of the games you list are much more CPU intensive than GPU intensive. RAM is cheap, too, and Wndows 7 has good file caching behavior, so sevral GBs of "free" RAM are put to good use.
Then, get a lower-end current video card. Lately, Radeon HD 6750s and 6770s have come down in price a bit, so finding a nice one shouldn't be too hard. If that's too much where you are, a GDDR5 Radeon HD 6670 would be a good cheaper option. If a 6790 can fit in your budget, a 6850 can fit, and would be a better buy, but getting that high might also warrant a bigger power supply, where most expandable PCs will have enough power for a 6770. Less than a 6670 could start being fairly limiting even for 14900x900, and would not be good enough if or when you get a higher-resolution monitor.
Intel's CPUs are far faster than AMD's, today, and most of the games you list are much more CPU intensive than GPU intensive. RAM is cheap, too, and Wndows 7 has good file caching behavior, so sevral GBs of "free" RAM are put to good use.
Then, get a lower-end current video card. Lately, Radeon HD 6750s and 6770s have come down in price a bit, so finding a nice one shouldn't be too hard. If that's too much where you are, a GDDR5 Radeon HD 6670 would be a good cheaper option. If a 6790 can fit in your budget, a 6850 can fit, and would be a better buy, but getting that high might also warrant a bigger power supply, where most expandable PCs will have enough power for a 6770. Less than a 6670 could start being fairly limiting even for 14900x900, and would not be good enough if or when you get a higher-resolution monitor.
