Help with AMD 64 3200 vs AMD 3800 x2

Currently I am using a Pentium M 1.7 with 1gig ram and integrated graphics on my laptop and I can play World of Warcraft in window mode and surf the net with a little lag. However, using outlook for emails at the same time is super laggy. If I play on a PC with the 3200 and a video card, will doing stuff while the game is running have any lag when using applications? Or will the dual core 3800 be better?

I'm comparing the 3200 to the 3800 because those are the cheapest 939 processors in their category.

On a similar vein, what are you guys doing with your old CPUs?
I'm about to upgrade my 3000+ to a 3800+ X2.
I also have a leftober socket 939 MB and AGP card.
Should I sell the parts separately on Ebay, put them in one of my old cases and sell it together as a computer -- hold it as a spare?
Is there a better alternative to Ebay that folks here use?