Thoughts about upgrading my computer.

So. First off, I'd just like to say it's my first post and I've found these forums so useful in my hardware ventures and just general enjoyment.

Now, on to business. I have a decent computer, ~$1500 including the purchase of my 19 inch LCD monitor about a year ago. My computer is as follows.

AMD Athlon(tm) 64 Processor 3200+, MMX, 3DNow, ~2.0GHz
2 GB (2x Kingston 1024MB PC3200 DDR 400MHz (2 x 512MB))
Asus A8N-SLI deluxe
1, 80 GB; 1, 164 GB
NVIDIA GeForce 7800 GT
SyncMaster 915N
Sound Blaster Live! 24-bit (My sound never worked on my mobo, and I just put in a spare soundcard)

I reeeeaaallly want to upgrade my processor to a dual core soon, and I was thinking of just going cheap and purchasing a X2 3800+ and over clocking it a bit. I play plenty of games all the time, and I often have one windowed and a bunch of applications running, thus my desire for a dual core. This got me thinking. Should I just go to the AM2 and buy a new mobo? I prolly won't be getting a quad core the first month, maybe not even the first year, it comes out. I'd really like some feed back as to what everyone would think would be the best and most cost efficient and everything else inbetween.

Thanks in advance,
Draylorre

What about the PSU? (or does that fall into a secondary importance category?)

Not necessaliry, A 3800 will last a good amount of time, and show some performance, overclocked or not. The 65nm cores are coming out, so spending more is useless(got this from shadowduck, 100 percent agreement with him). Unless you want to shell out more cash, then yes upgrade to a 4200 or 4400.