Except for the vista option at the time I chose the xps-420 with 8GB ram and I am still extremely pleased with it. That was about three years ago. Or whenever they came out.
Don't like vista to much, I am pro xp pro.
Right now I am looking at the sony 24" all in one unit. For a replacement for my home built 800mhz desktop.
Sleek small footprint with about everything you would want in a desktop at a very competitive price.
It has windows 7 which I have no exposure to.
So far the only draw back I see is every device is integrated to the board except for the hard drive and the optical drive.