You SHOULD compare prices on Newegg and Tigerdirect. Newegg usually has the best selection and the lowest prices.
If you can get an intel i7 930 customized computer for $1300, that is a very good deal, because I have priced a number of them based on that cpu and they come up around $1500. The AMD Hex Core is unbeatable, and is comparable to a higher Intel i7 CPU than the 930. From what I have read in Maximum PC Magazine, the new AMD hexcore is performing at a level of about intel i7 960. So for $200 for the 1055T, that is a real steal. There is one more, the 1090T which costs about $100 more than the 1055T, both are hex core cpu's. The AMD hexcore processors cannot beat the new Intel 890x however, just be aware of that...but since most outfits want $1200 JUST for the Intel hexcore cpu, $200 - $300 is a steal.
Never EVER short yourself on the motherboard. I consider the motherboard to be the most critical component in the computer, more critical even than the cpu itself. The reason why is because everything is plugged into the motherboard. The chipsets are what determine how good the communications are between RAM and cpu and Videocard and cpu, the other two critical functions.
With motherboards YOU GET WHAT YOU PAY FOR...buy cheap boards, get cheap performance, buy good, get good, buy excellent, well...sometimes you get something better than excellent. I don't care how good all of the rest of the components are, if you cheat yourself on the motherboard, you will have a mediocre to rotten computer.
The fortunate thing about the new AMD hexcore cpu's is that AMD decided to keep the AM3 motherboards rather than create a new socket for them. This means that there are some really excellent motherboards out there that are AM3 that will be entirely compatible with the new hexcore
cpu's. Make sure whatever you pick, the manufacturer tells you - it is AMD hexcore compatible.
Windows 7 64 bit is what I would use, and nothing less - no 32 bit version! Using less than 4 gigs is crazy on a computer like this, for RAM. I think the ideal on a computer like this is 6 - 8 gigs of RAM, dual channeled to get the highest possible speed. The nice thing is that the AM3 motherboards take DDR3, so you already get the advantage of the higher clock speeds. I would stick with 6 Gigs if you are trying to keep the cost under control, and add more later if you want to.
The brand new nVidia GTX card with fermi enabled is able to SLIGHTLY beat AMD's HD 5970 card, but is the extra 50 Watts of actual power consumption worth the little bit of gain? The AMD cards run cooler. Since you don't need to play Crysis on ultra high or high settings, what do you need these expensive cards for? I think your choice of an AMD HD 5770 is a good choice.
THe instructions to build a computer are very straight forward. There are about 10 - 12 steps to do it, no matter what components you are installing except if you decide to install a RAID configuration which will require some additional hardware and know-how. Otherwise, a standard build is simple and efficient. You can BUY a magazine at Barnes and Noble on how to build one for about $15 which shows you all the components and steps you through, step by step. Or, you can watch a number of Youtubes, there are plenty of them that show you how to do it. Or you can get on line and google "How to build a computer."
Here are a couple I got:
http://www.wikihow.com/Build-a-Computer
http://www.pcmech.com/byopc/
http://www.google.com/webhp?sourceid=navclient-ff#q=How+to+build+a+computer&hl=en&prmd=v&source=univ&tbs=vid:1&tbo=u&ei=O6A-TPvNLsnpnQepueWTBQ&sa=X&oi=video_result_group&ct=title&resnum=4&ved=0CD0QqwQwAw&fp=d04041bc77eb0df0
Plenty of sites on the net show you how. It is easy.
Get an OEM copy of the operating system. Windows 7 Home Premium OEM is $99 on Newegg.
The important point, if you are going to build it yourself, is to decide on all the components first. Then, study the specifications for those components. So, before you decide on which motherboard, study and compare the specs of several motherboards and find out which has the mostest features for the bucks. Then, when you settle on one or two, download the motherboard manual(s) for them and then read through before you make a purchase - this is the SMART way to do it.
I figure, anyone who buys less than a 1 Teribyte hard disk, has to either have a serious hole in their wallet or a serious hole in their head. Last Friday, I saw a 1 Teribyte new 7200 RPM SATA 3 from Western Digital on sale for $68 from Fry's Electronics (they have a site on line too).
DO NOT cheat yourself on the power supply!Do not buy a cheap one and do not buy a small one. For this computer, at least a 650 Watt PSU, either Corsair or ANTEC. I would feel more comfortable these days with a 750 Watt PSU.