Hi, sorry, i'm new to the forums so bear with me if this is in the wrong section.
Basically I'm thinking about upgrading.  Current system is:
Pentium D 830 3.0Ghz
Asus PL5D2 Motherboard
Geforce 6600le
2 GB RAM
 
The hdd is fine. The power supply is a Mushkin 550w, i think thats fine for most things.
 
Should I bother with an upgrade or just build a new system?
A budget of roughly $400-$500 for a CPU, motherboard and video card.  Anything more than $600 then I would probably think about getting a new rig.
Any suggestions would be greatly appreciated...
Thanks!

Well, depending on what you'd like to accomplish, spending just $150 on a new video card will make a howling difference.

Yeah I thought about going out to just grab a vid card...but I thought that its not as effective with an old CPU.
 
The mission is to play games....better.  It doesn't need to run Oblivion on max settings with AA on a crazy high resolution or anything like that.  Just an improvement over what I got now.

If you just want to run at stock (I don't know how much that board will OC), you might be very happy with a 9600GT.

^Agreed.