Vista Icons are big by default, you can make them smaller, but Microsoft wanted to make windows seem more steamline and "fresh" So the larger images seemed less of a linear thing, give it a move 3D feel rather than just images on the bottom level of the pc
I'll bost a pic of my desktop soon, I have 2 (My Notebook is Media Center, Desktop is Vista) I don't plan on putting vista on my notebook any time soon.. Lol It's too unrefined lol, The Betas have too many problems with them as of vet