Ok, took me a while to get back to this post....but here is the system I would build 4 u!
Everything I try to get is versitile and upgradable. I like big cases and mobos with lots of features that are overclockable!
CASE/PSU :Antec Performance Plus Series Plus1080AMG w/ 430 antec true power psu $116-zipzoomfly.com
MOBO :Asus P4C800 Deluxe i875P $165-zipzoomfly.com (there are so many good mobo's, this is such a hard one to pick for people, it all in exactly what they want from it!)
PROC : Intel Pentium 4 Prescott Processor 3GHz, 800MHz FSB, Socket 478, 1MB Cache $224-zipzoomfly.com
OPTICAL DRIVE :Plextor PX708A Internal DVD±R/RW & CD-R/RW $129 (after $30 rebate)-zipzoomfly.com
HARD DRIVE : u have (seen and bought maxtor 250g 8mb HD's for $150)
SOUND : u have (also onboard sound on the mobo)
VIDEO : u have (always suggest getting the biggest you can afford! The new Nvidias coming out seem to kick ass in all reviews, but we are yet to see what ATI will release)
Total price ordering all these new parts from zipzoomfly.com ~$635 U.S. This price is assuming you are using your own HD, video, and sound that you already have!
You want to spend more....well there is ALWAYS better and faster to get!
***********EDIT................OH SHIT...I forgot memory....
Corsair VS1GBKIT400 1GB Kit DDR400 PC3200 CAS2.5 $199
This will put you way over budget, so you can buy 1 stick for now and 1 later! That will keep you in your budget!