Looking for a budgetted gaming PC!! help

Hey, i am in need of help of building a budgeted gaming PC with advice and suggestions.
MOST LIKELY WILL NOT BE OVERCLOCKING
www.newegg.ca - main website i wish to attain to.
I want to get the best performance and bang for the buck!
I want to be able to run games with great fps with out lag.. I was thinking about the following so far:
I am not too sure if everything fits properly, I didnt give much look into it yet.

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APPROXIMATE PURCHASE DATE: (Hopefully within the next month) BUDGET RANGE: (600-800) Before / After Rebates

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: (gaming, watching movies/tv shows, researching/schooling)

PARTS NOT REQUIRED: (dont need keyboard, mouse or monitor)

PREFERRED WEBSITE(S) FOR PARTS: www.newegg.ca

PARTS PREFERENCES: Was hoping to go with an AMD Phenom ii x4 955 build(heard great things about this cpu) and has an amazing price.

OVERCLOCKING: Probably not. SLI OR CROSSFIRE: Not atm

MONITOR RESOLUTION: Im running 1280x1024 right now

ADDITIONAL COMMENTS: I want best performance & best bang for the buck. GAMING.

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GIGABYTE GA-MA770T-UD3P AM3 AMD 770 ATX AMD
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...


AMD Phenom II X4 955 Black Edition Deneb 3.2GHz Socket AM3 125W Quad-Core Processor
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...



G.SKILL 2GB (2 x 1GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit Desktop Memory
http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...

Seagate Barracuda 7200.12 ST3250318AS 250GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...


This is all I have right now.. If you guys could provide me with any advice, and fill in the blanks for (GPU, PSU.. etc) that would be appreciated!

I am looking to run with the Phenom II X4 955 Processor since it's cheap and i've heard great things about this cpu.