Don't think I've ever seen it posted before but this is a fantastic site where I've been getting a load of wallpapers from for ages (both high res and high image quality).
My work desktop. According to the IT department, mere users like us can't be trusted with highly sensitive & technical things like wallpapers or screensaver settings
He has Windows Vista I think, which has the sidebar by default, but there are other programs you can do this with.
Like Stardock's sidebar etc...I don't know which one to recommend since I don't use this kind of bar and I prefer Yahoo widgets!