HP Pavilion Upgrade

Hi!

This is my first build/upgrade attempt and I've read this site religiously while deciding on what to do. My computer is the HP Pavilion p6243a (NY799AA) **http://partsurfer.hp.com/Search.aspx?type=PROD&SearchTe...**. I plan on adding a graphics card so I can get off my integrated card on my motherboard. I also plan on upgrading the 2.1 GHz Sempron that came stock with the box system. Finally, I want to add a new power supply to feed power to all that new hardware that my 250W just won't handle. After shopping around and reading up, I decided to go with all new parts from a reputable vendor (NewEgg) that would warranty my parts if they failed during the initial stress test. Here are the three pieces of hardware that I've selected to use..

CPU: AMD Phenom II X4 965 Black Edition Deneb 3.4 GHz Socket AM3 Quad-Core Processor HDZ965fbgmbox
GPU: Gigabyte GV-N550D5-1GI GeForce GTX 550 Ti (Fermi) 1GB 192-bit GDDR5 PCI Express 2.0 x16 HDCP w/ SLI support
PSU: Cooler Master GX Series RS650-ACAAE3-US 650W ATX 12v 80 Plus

I've selected the Phenom II X4 based on my need for speed. I require high frame rates and no hiccups for online FPS games and MMO's. I figured that when I upgraded my motherboard in the future to support a Dual GPU interface, I could just switch the processor out onto a sleek new motherboard or case on a future build.

The graphics card I picked based off several reviews that I've read and its ability to run in the SLI interface. The power it puts out should be more than enough to keep me happy till new innovations call for an upgrade to my machine.

Lastly, I selected my PSU based off the assumption that I will indeed be increasing my computers power use with a motherboard and additional GPU in the future.

I'm pretty darn sure that all of the hardware parts I'm swapping in will actually fit in my case and should be compatible with the rest of my system. Any tweaks or changes anyone see that I could do?

Cheers,
A. Clay