I am going to install Ubuntu 10 on this old machine (3GHz, 2GB RAM, 1 TB HD, nVidia 6200) but will run XP as an application in order to run games. I am thinking of VMware - only b/c it's the only one I know. Can any one suggest others, or recommend this one?
VMWare is OK, but VisualBox from Oracle (formerly Solaris) is better in many respects. Just be aware that games are going to perform extremely pooly in a VM. If you want to run games you would be better of dual-booting.
What if I only play single player games - nothing online? If your answer is the same, then I guess I will dual boot. ... still having the stain that is Windows on my machine is so annoying.
It depends upon the graphics requirements. The graphics card that a VM uses is an emulated one with nowehre near the power of your real graphics card. But VirtualBox does support some of the 3D features of your graphics card.
On the other hand, it does no harm to give it a try. All you can lose is an hour or two of your time, and it's always fun to play. If the games don't perform to your satisfaction in a VM then go for dual booting.