I had heard that Vista was buggy. An IT bud of mine explained that Vista runs using ALL of the available RAM; regardless of how much you have or add, it will allocate it for use. Apprently this make for slow operation.
I was wanting to get my daughter a laptop for Christmas and had gotten an email from Dell with some good deals, but they all come with Vista. I am thinkng about a Mac for her but they are more pricy right out of the gate.