Looking for some advise about this build

I am looking at getting the basics of a new rig and using some of my components off of my other system.
I have a tower, Antec 300.
I have CD/DVD drives.
I have a PSU, but i am not sure i trust it, AGI U580UB, I was looking at getting a more reliable brand.
If you think this PSU is good let me know as it would take off $100.
Also i was thinking about a moduar PSU, but they cost more obviously and i wasn't so sure i should lower the wattage.

Here is what i am looking at.
--------------------------------------------------------------------------------------------------------------
PSU
CORSAIR CMPSU-750TX 750W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Compatible with Core i7 Power Supply - Retail
http://www.newegg.com/Product/Prod [...] 6817139006

MOBO
GIGABYTE GA-MA770T-UD3P AM3 AMD 770 ATX AMD Motherboard - Retail
http://www.newegg.com/Product/Prod [...] 6813128392

GPU
ASUS EAH5770/2DIS/1GD5/V2 Radeon HD 5770 1GB 128-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card - Retail
http://www.newegg.com/Product/Prod [...] 6814121355

CPU
AMD Phenom II X4 945 Deneb 3.0GHz Socket AM3 95W Quad-Core Processor Model HDX945WFGIBOX - Retail
http://www.newegg.com/Product/Prod [...] 6819103696

RAM
G.SKILL Ripjaws Series 8GB (4 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9Q-8GBRL - Retail
http://www.newegg.com/Product/Prod [...] 6820231325

HDD
Western Digital Caviar SE16 WD3200KSRTL 320GB 7200 RPM SATA 3.0Gb/s 3.5" Hard Drive -Retail
http://www.newegg.com/Product/Prod [...] 6822136039
---------------------------------------------------------------------------------------------------------------
I am hoping to play near any game on max settings, but this is a little over my budget.
I was hoping to keep it at around $650-$700.
Besides gaming I do a little of everything...

I need a new HDD because mine is old and only an 80gig that runs at 5400rpm.
I also would like it to have a little room for upgrades as time moves on, but overall i would like it to last 4-5 years.

I was thinking of making it a little more energy efficient, but kinda lost sight of that. Heh.

Any advice would be welcomed and i am looking to buy this all about a week after x-mas.

Thanks!