Ok, here is another design:
Base:
Case/PSU
Antec LifeStyle SONATA II, Piano Black (Includes a 450W SmatPower 2.0 PSU, also includes a 120mm case fan) $104.99
http://www.newegg.com/Product/Produc...82E16811129155
HDD
Seagate 250GB 8MB Cache 7200.10 (SATAII) $79.99
http://www.newegg.com/Product/Produc...82E16822148142
DVD Burner
Pioneer 111D (Black) $35.99
http://www.newegg.com/Product/Produc...82E16827129001
Operating System
Windows XP Pro w/ SP2 OEM $137.99
http://www.newegg.com/Product/Produc...82E16837102062
Additional
Sunbeam Front Panel $25.99
http://www.newegg.com/Product/Produc...82E16811998811
Logitech Cordless DesktopS 510 $57.99
http://www.newegg.com/Product/Produc...82E16823126180
AMD System (Skt939)
Motherboard
Asus A8N-VM CSM $78.99 (Has on board GeForce 6150)
http://www.newegg.com/Product/Produc...82E16813131570
CPU
AMD Athlon 64 3800+ $147.99
http://www.newegg.com/Product/Produc...82E16819103531
RAM
Crucial Technology Ballistix 1GB (2 x 512MB) $95.99
http://www.newegg.com/Product/Produc...82E16820148007
AMD System (Skt AM2)
CPU
AMD Athlon64 3800+ $145.99
http://www.newegg.com/Product/Produc...82E16819103631
Motherboard
Asus M2NPV-VM (Has on board GeForce 6150) $84.99
http://www.newegg.com/Product/Produc...82E16813131014
RAM
OCZ Gold 1GB (2 x 512MB) DDR2-800 $112.99
http://www.newegg.com/Product/Produc...82E16820227126
Intel System (Skt 775)
CPU
Intel Pentium 4 511 Prescott 533MHz FSB 1MB L2 Cache $105.99
http://www.newegg.com/Product/Produc...82E16819116013
Motherboard
Asus P5LD2-VM $108.99
http://www.newegg.com/Product/Produc...82E16813131545
RAM
OCZ Gold 1GB (2 x 512MB) DDR2-800 $112.99
http://www.newegg.com/Product/Produc...82E16820227126
AMD (Skt 939) System $765.91
AMD (Skt AM2) System $786.91 (Is new technology, hence the slightly higher price)
Intel (Skt 775) System $770.91
This is the best I could come up with, it will do what you want it to do, and it will have decent cooling already. And all systems allow you to upgrade later on if needed.