I came across a Windows Sidebar gadget the other day which is actually proving to be useful - the Microsoft Office 2007 Recently Used Documents gadget. It’s quite handy having a list of your recent documents available without having to go through the Start Menu. I recommend checking this one out.
At this stage it only supports Word, Excel and PowerPoint documents, hopefully there will be support for more document types in later versions. There’s the docked state on the right which includes a fly out when you click more, and here’s the undocked state: