A Solid Performer

[AMD_RULES]

I'm looking to assemble a new computer to replace our main household computer which is an HP a700y with a P4 2.8Ghz Socket 478, 1GB DDR Memory, and a 160GB ATA Hard Drive. We want something fast, even if it's overkill. I do not want a off the shelf computer either, such as a Dell. I would also prefer to buy most if not all of the parts from Newegg.com. I do live near a Microcenter, but I like Newegg better.

1) What will you be doing with this PC? Gaming? Photoshop? Web browsing? etc
Email, Web Browsing, Quickbooks, Microsoft Office, Light Music/Picture/Video Editing, HD Movie Playback
2) What's your budget? Are tax and shipping included?
$500... tax and shipping are not part of the budget
3) Where do you live?
Pennsylvania
4) What exact parts do you need for that budget? CPU, RAM, case, etc. "Everything" is not a valid answer. Please list out all the parts you'll need.
Case, PSU, RAM, Motherboard, CPU, Hard Drive, Case, Etc. I need all the components that make up a computer.
5) If reusing any parts, what parts will you be reusing? Please be especially specific about the power supply. List make and model.
No parts will be reused.
6) Will you be overclocking?
Nope...
7) What size monitor do you have and/or plan to have?
Looking to purchase a 20 or 22 inch widescreen LCD Monitor (Not part of the budget listed above)
8) When do you plan on building/buying the PC?
Within the next two months
9) What features do you need in a motherboard? RAID? Firewire? Crossfire or SLI support? etc.
Plenty of USB Ports would be great.
10) Do you already have a legit and reusable/transferable OS key/license? If yes, what OS? 32bit or 64bit?
I will need a copy of Windows, preferrably Win7 Home Premium x64.

 

[Deluded]

No GPU, because the motherboard has onboard video and should be capable of HD playback.