C:\Windows\System32\msinfo32.exe is a tool that has been around for a while, but it is not always easy to find so many don't know about it. This utility displays a wealth of information about your system including:

Summary: OS name, version, system name, system manufacturer and model, processor and BIOS information, time zone, and memory details

Hardware Resources: Conflicts and sharing, DMA, I/O, IRQs and memory.

Components: This includes all hardware as you might otherwise view it in device manager, with the properties of each exposed when selected. Components may include devices such as: multimedia , CD-ROM , sound , display, IR, input ,modem, network, ports, storage, printing, and USB.

Software Environment: system drivers, signed drivers, environment variables, print jobs, network connections, running tasks, loaded modules, services, program groups, startup programs, OLE registration, and Windows error reporting.

Most every bit of this information can be found elsewhere in Windows Vista (often by selecting what ever it is and choosing properties) but this is a great one-stop place for tons of details on everything which can save time when you are looking for the place you might otherwise find these details.