For the vid card: What's the price of the ATI 9700Pro where you are?
If it's the same as the FX5600, go with the 9700Pro... apparently they are on the same plane in terms of performance and features, and I've heard nothing but good things about the 9700Pro. The GeForce FX series, OTOH, doesn't really appear to be "next generation" over the GeForce Ti series... and there's apparently some screwing around with the drivers on the FX series, cheating in the scores that 3DMark produces (nothing new really, nVidia has been doing that with the GF3 and GF4 drivers for a while now.... only way they can say that the new drivers improve performance by 15-30%)
With that system, you *CAN* stick with Windows 98... do you have many USB devices? If you do, and you get the "Unknown Device" problem when installing those devices or upon bootup, you will have to update to Win98Second Edition (free upgrade I believe, through MS website) and get the updated uhcd.sys file for Win98SE.
Certain optical USB trackballs, mice, printers, scanners and the USB Saitek X36&X45 will produce these problems.
The rest looks pretty decent, except I dunno what this is:
COOLER MASTER HHCL61 SilentHeatPipe Sock.A XP2.X
For the memory, I believe that particular XP chip doesn't operate at more than 266Mhz Front Side Bus... so I don't see how you can go wrong with something slightly slower than 400Mhz, since the memory can't be accessed faster than the Bus can allocate.
IMO.
-SW