What do you guys think about this

It's a good upgrade but consider this:

1. Given DDR2 prices right now, you may as well go with DDR3

2. Again, with similar prices, go with a AM3 motherboard

3. The 9800GTX is old now. Consider a 5750/5770/5850.

Btw, I'm basing prices off Newegg prices right now.

I assume, that the processor that you mention is the X4 955 BE.

For the mobo try to get the M4A79T Deluxe and DDR3 4GB. Also, a better GPU is an option.

What is the principal objet of the rig? Games, surf the web, video edition....

Given us all the specifications.

1- CPU
2- GPU
3- RAM
4- HDD
5- MOBO
6- PSU

With this parts, here in the forum can help you a little more.