trying to build a system, need some tips. did some research

[GhettoPeanut]

I've decided to upgrade my system (with the help of my techie buddy). he told me this was a good place to double check what i'm doing.

for the motherboard i'm thinking:
MSI "K8N Neo4 Platinum" NVIDIA nForce4 Ultra Chipset Motherboard For AMD Socket 939 CPU

for a video card
MSI nVIDIA GeForce 6800

and for a cpu i was gonna go with a:
AMD Athlon 64 3500+ 2.2 GHz

My questions are as follows.
1 - do these products conflict with each other? i'd hate to buy a mother board that couldn't use the cpu.
2 - should i worry about my current sound card/network card not being compatable?
3 - general pro's and cons? what might you do in this situation?

this is going to be for gaming mostly.

 

[inspiron8200guy]

If you are going to be doing a lot of gaming and maybe some video editing the graphics card may need a second look. I have heard of numerous problems with nVidia and Half Life 2. An ATI is the better way to go. If you have no plans to seriously play HL2 then the nVidia will do fine. I currently have a nVidia card and had a huge HL2 crashing problem.

 

[GhettoPeanut]

thanks for the input, i was infact going to be playing Half Life 2. so i did some more looking for ATI cards instead (orriginally chose the nVidia cuz of the MSI similarity with the motherboard.

so i'm looking at this one now, seems pretty beefy and the reviews seem pretty good
ATI Radeon X700 PRO

so once again, think this will work with the orriginal Motherboard and CPU mentioned in the first post? got any better ideas anyone?

i also noticed theres a PCI Express and a PCI Express X16, whats the difference?
-nvm it just seems to be a speed thing of types PCI Express: x1, x2, x4, x8 and x16