www.pricewatch.com if you weren't aware of it.
Three reliable merchants with great service (which is tough to find these days)
www.newegg.com
www.mwave.com
www.monarchcomputer.com
Way to check merchants out before you order.
www.resellerratings.com
Few things... for a few bucks more ($185) you can pick up a Retail 2.4GHZ P4 C stepping with a 800MHZ bus. These processors overclock on average to 3.2GHZ, have a faster bus = more performance, and hyperthreading which basically means that it tricks Windows XP/2K into thinking that you have a multiprocessor system (has to be the Pro version of the OS)... essentially you can multitask with CPU intensive applications with ease. So you could run a backup of your system, burn a CD and encode a MP3 at the same time. Very nice thing to have.
There are great deals all the time on hard drives. Look in the hot deals section of the CDRLabs forum.
For example I saw a deal on slickdeals for a 160GB Maxtor Hard drive for $80 after rebates. Don't need a hard drive eh? You say that now, until you start adding apps, a few videos, some MP3s etc... it's very enabling to have a large hard drive. I picked up a 180GB drive... 6 weeks later it's 75% full.
Here's a couple deal sites. There are more in a sticky thread at the Top of the Hot Deals forum.
www.slickdeals.net
www.fatwallet.com
www.techbargains.com
Motherboards... I'd look at an Abit IC7 for $137 @ Newegg, great deal for an awesome motherboard. If that's too much I'd look at the Abit IS7 or the Asus P4P800/400 can't remember which # it is. You want a motherboard that takes full advantage of that CPU.
Memory, you want PC2700/PC3200 (preferably the latter).
www.corsair.com or try the merchants listed above. I'd say stick with Corsair, Kingston, Samsung, TwinMos... most other brands you run into quality and compatibility issues. There's a deal on slickdeals for 512MB of Crucial PC2700 for $43. Take a look but you might want to move quick. A lot of these deals expire within a few days. I would recommend going with PC3200 though. PC1600 is a waste of your time. Though at a minimum, I'd say go with 512MB.
Graphics cards... I'd look at a Radeon 9600 not a 9200. 9200 won't do well with newer games. You could also look @ the NVIDIA 5600 based cards, but the 9600 offers better performance at a cheaper price.
Lastly, one thing most people forget about. Power Supply. You need a decent one or your system will have a fair number of stability issues. I'd recommend an Antec PSU, preferrably 380W or above. If you skimp or go with a generic brand, you can have major problems, burn out components etc.. All the merchants I listed above carry PSUs.