Additional Comments: I have my 8400GS hooked up to 26" monitor using DVI to HDMI cable.
I'm currently running on this.
The only games I can run on this are CSS at 1336x768 with FPS CFG, and TF2 at 800x600 with FPS CFG, and AVG FPS on TF2 is 18FPS.
He said no CF/SLI so get that 500w. That is a little bit over $500 though. I would try to go for an i3-2100 for $120 and a cheap h61 board for like $60. If you ever want to change to a bulldozer CPU, none of the am3+ mobos (good ones) are under $100 so just an idea...
Maybe get like a 940 or something so you can save a few $
There really is not much you can do. If you want anything good you gotta be willing to spend more. I personally would try to find a better mobo just so it doesn't crap out on you. The 6770 should do fine if you don't plan on maxing at 1900x1200. Maybe add a little bit more $ for a better mobo?
It's a little cheaper than the Rosewill and is more reliable. It should be enough to run your computer just fine. If you want more assurance, I am currently using a Phenom II x4 955 BE with a Sapphire 6770 with the Corsair 430W (Also, Newegg's PSU calculator says that 432W is needed for a PII X4 w/ the 6770 but that is an overestimate).
If you intend to stay on lower resolutions, the 6770 should do you just fine. I'm running on a 1280x1024 monitor and I max out Crysis 2 and The Witcher 2 with playable FPS (Don't know how to check exact FPS without external programs.).
With the i3-2100 and the 1155 motherboard, I get $130 left for the video card, so I think I'll stay with the 6770. But if I go with the Phenom II X4, I get $140 to spend on video card, and I can get a used 6850 on Amazon for $141. I'll be ok with the 6770 if it can play with either of these CPUs with meduim settings,high textures at 1080p. I'll be playing at 1368x768 about 95% of the time and I think the 6850 is a little overkill, and doesn't have warranty too.