Hi Saintman,
I see you priced your parts with Newegg. From my calculations it comes to $1321.37. Other stuff you may need to consider that increases the overall price:
Operating System = WinXP home aprx $89
Card Reader/writer with Floppy = $30
Modem
Lan 10-100
Mouse & Keyboard
Speakers
Monitor
To decrease the cost:
The case at $175 (without PS) could be exchanged for a less expensive one (really).
Course the PS at $55 ads to it. Changing the PS to the Antec Model SP-500, (PCI-E ready), would cost $30 more.
Wondering about the Zalman cooling fan ($44.99) since the retail version of the P4 640 comes with a Heatsink and Fan. The current case you selected also has 3 fans 8m (course additional case fans are welcome & can be added later if needed)
I would suggest the Western Digital 250GB 7200 RPM over the Maxtor at about the same price.
The ATI Radeon X800XL at $299 is OK, however I would prefer the Nvidia GeForce 6800GT at $305 in Asus or $309 in Leadtec. The 6800 Ultra is a little rich in price at $425 to $570.
The Intel Pent 4 640 3.2GHz process is OK at $286.99. Sure the AMD Athlon 64 3500 Newcastle at $272, or the 3800 at $375.99 is a little faster in gaming, but the Motherboard would also need changing. You playing games at home would probably not be able to tell the difference in the 3 above processors (IMO.
The AMD fans will always holler that whenever Intel comes up or equals the speed of AMD that AMD will come out with another processor that is faster. Unless you are buying the absolute top of the line in either, entering competition looking for the gold, then spending all that money is ridiculous IMO, for very good high end gaming with current high tech games, and in the next several years. Heck, my 3 year old Pent 4, 2.0GHz, 512MB RAM, Nvidia Geforce4 TI4600 video card, plays Doom3, Half-Life 2, FarCry, Halo, All the Medel of Honor series, Flight Simulators, NASCAR series, Battlefield series, Call of Duty, Brothers in Arms....etc...pretty dang good. When I find a new game that plays bad, I'll look at buying one of those cheapo emachines (selling the monitor & printer to reduce cost below $550), that has a Athlon 64 3200 processor, and upgrade the Graphics/RAM which should then last at least another 3-4 years in gaming. 
If this is your 1st time in building....it is not for everyone. I always like to advise people to build a very, very cheap machine for the 1st time.
You might try comparing the cost of having someone else build that would give a warranty, so that you don't have to look to yourself when things go south. One company that gives parts just as good as Newegge and charges $49 to build is Monarch:
http://www.monarchcomputer.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=M&Category_Code=allcustom