$500 Work Build Custom Rig? Please Help!

My dad is running a Celeron Compaq computer with 1GB of ddr ram. The computer was 8 years old! I have a i7 rig and he used it for a day when his computer crashed and now he wants one like mine that is fast. I didn't buy the parts, I bought it in a lot on ebay for $800 and built the PC. I'd like a build for him so I can buy the parts and put a pc together for him. Here is his requirements:

APPROXIMATE PURCHASE DATE: end of the month of Feb/2010

BUDGET RANGE: Around $500 After Rebates AT MOST is $600

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Surfing the Web and Outlook, Light Photoshoping

PARTS NOT REQUIRED: OS, Keyboard, Mouse, Monitor, Speakers,

PREFERRED WEBSITE(S) FOR PARTS: newegg.com & tigerdirect.com other sites might be considered
COUNTRY OF ORIGIN: USA

PARTS PREFERENCES: INTEL PROCESSOR! NO AMD! I don't know why but my dad hates AMD. I think a Core 2 Duo or a Quad would fit best for him. I think an i7 is overkill for him.

OVERCLOCKING: Maybe(just a little)

SLI OR CROSSFIRE: Maybe(I'd do it with dual 4350's)

MONITOR RESOLUTION: Again here is doesn't matter to him. I think the standard HDMI resolution is what will work

ADDITIONAL COMMENTS: He needs atleast a 250GB HDD but a 500GB is recommended. Also a semi-low graphics would be nice for Photoshop, I have a Radeon 4350 and might buy another one and SLI it so I'd like a SLI board. I'd only overclock it maybe .5Ghz or 1Ghz, that too if the Processor has nice airflow. I need a nice parts list. I would like for him to have 2GB or 4GB in Dual Channel. So yeah that is about it. Also if anyone has a nice monitor recommendation OVER 24" that can go into portrait mode please let me know because I need one. Thanks!