This isn't anything new, but for those who want the full Vista/Se7en Experience on XP, there is a way to bypass the 72px icon size limitation; but you can't adjust it in Display Properties. I found a tweak that can enable ANY size icon up to 256px I believe; it didn't mention anything about a max. size. It can be found at http://www.tweakxp.com/article36783.aspx. As you can tell, the tweak is EXTREMELY OLD (from 2002) and mentions Mac OSX rather than Vista.
From my experience, I really enjoy having 128px icons on my Desktop & in Windows Explorer. The quality of the icons are just as great as Vista's; however, most XP icons only go up to 48px and therefore pixelate beyond that. But there are countless icons on the web now that are 128px or 256px. To enable the enlarged icon view, click the "Views" button in Explorer and select "Icons". "Tile" and "Thumbnail" views don't change a bit.
There are a few things I disliked though, the Start Menu icons are at the same resolution as the desktop icons, and navigation can get quite annoying. And whenever you adjust anything on the Display Properties under the "Appearance" tab, the icon size resets back to 72px.
A Word of Advice: Before deciding on a new icon size, know the one key difference between XP & Vista's icon rendering techniques: Vista's icons use vectors (calculations), while XP's icons are rasterized (pixelated), so I don't recommend any other size than 128px or 256px unless if you want pixelation on every single icon.
