Hi .Im trying to decide what kind of system should i get...Im mainly gaming (90%) so here i go:

E8400
Asus EN8800GTS-TOP
MB Asus P5K-E
4Gb DDR2 800MHz Corsair

Do you think i should get a Asus EN8800GT-TOP an invest the money in 8gb ddr2? i run windows xp...would there be problems?

If you are running Windows XP (32 bit), then it will only see 3-3.3 (maybe 3.5) GB.

The p5k-e is a P35 board. Many would suggest that you may want to look into P45 board - it's similar, but newer tech - plus supports PCI 2.0.

You need a 64 bit operating system to utilize more than 4 GB of memory. I would suggest you get the 2x2GB kits, instead of 4x1GB, so you'll have room for more memory if you ever were to get a 64 bit operating system.

The 8400 is a wonderful CPU.

My 8800 GTS has been good to me so far.

Good luck.

E8400: Good
Motherboard: Ok, MSI Neo-3R or Asus P5Q Pro better (P45) as huron points out.
Video card: 4850- smacks 8800GT(S) around
Memory: Good make sure its 4-4-4-12, and huron is right about OS.

"
The p5k-e is a P35 board. Many would suggest that you may want to look into P45 board - it's similar, but newer tech - plus supports PCI 2.0.

"

Do you have something specific in mind?

Look at my post Hory- I recommend two good P45 boards.