Which one is right for me?

We recommend Windows Vista Ultimate. The most complete edition of Windows Vista—with the power, security, and mobility features that you need for work, and all of the entertainment features that you want for fun.

32-bit vs. 64-bit Operating System

The difference between the 32-bit and 64-bit Operating Systems is that the 64-bit version will benefit from the 64-bit architecture of modern CPUs resulting in improved performance and stability.

In addition 64-bit Operating System support an almost unlimited amount of RAM, whereas 32-bit Operating Systems can only see up to around 3GB of system RAM. Other issues to consider are compatibility and stability, there are some older peripherals that may not function on 64-bit Operating Systems, but most of the new peripherals from major brands are compatible with all versions of Vista.