[Solved] Budget Photoshop/Illustrator machine

APPROXIMATE PURCHASE DATE: this week
BUDGET RANGE: 500-600 After Rebates (unless I need to spend more)
SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Photoshop/Illustrator/Indesign CS4, Outlook, Web Browsing, light video editing
PARTS NOT REQUIRED: Keyboard, Mouse, Display
PREFERRED WEBSITE(S) FOR PARTS: newegg.com (but I'm flexible)
PARTS PREFERENCES:
OVERCLOCKING: No
SLI OR CROSSFIRE: No
MONITOR RESOLUTION: 1920x1080 (dvi preferrable)
ADDITIONAL COMMENTS: (see below)

Cool and quiet is big plus

Wife currently has an old Dell Precision Workstation 370 with the following basic specs:

Processor: P4 520 (2.8MHz)
Memory: 2.5 GB

The machine gets bogged down pretty badly currently. I suspect it is a combination of being underpowered and OS (XP) rot.

Is it realistic to think that I can build/buy her a new box that will run Photoshop/Illustrator CS4 reasonably well for $500-600? I can spend more if really necessary, but this is really more of a hobby for her.

I was thinking I would budget as follows:

Motherboard: ? ($100)
Processor: Intel quad-core 2.5GHz ($160)
Memory: 4 GB ram ($100)
Case and PS: ($80) (could I reuse Dell case/PS, or have things changed too much?)
HD: 1TB Sata ($100)
DVD Burner: ($40)

I didn't include a video card... this is a point of confusion for me. I'm under the impression that onboard video from many MBs may be sufficient for CS4. Is that true?

Also, can the Dell case/PS be reused, or has technology changed too much?

Thanks!