In this example we are in Details view which gives you more data about the files youre looking at.
After clicking it once we see we have the Tiles View.
Extra Large ViewThe one view not available by simply clicking the Change your view button is Extra Large Icons.
To get the Extra Large setting nudge the arrow button for More Options.
Then at the top of the menu select Extra Large Icons.
In this example we see some default Windows 7 wallpaper icons as Extra Large.
It can be done in Vista as well by clicking the Views button and selecting Extra Large Icons.