If you're looking to tweak Windows 7 in just about any way possible--as well as gather important system information--you'll do well to try out EnhanceMySe7en Pro ($30, 15-day free trial). It's a combination system customizer, diagnostics tool, and maintenance tool rolled into one.
Those who want to keep their systems in tip-top shape will welcome EnhanceMySe7en Pro's Registry Cleaner, Disk Cleaner, hard drive monitor, and similar tools, which do a very good job of ensuring your system is problem-free. You can also decide which programs to load at startup, and monitor your hard drive's performance and health and temperature. Most of the tools are straightforward to use, but some require a fair amount of technical know-how if they are to be put to the best use. For example, in the Memory, Cache section you'll need to know the ideal CPU Second Level Cache setting.
There's plenty to EnhanceMySe7en Pro beyond maintenance, and the program has a particularly powerful set of system tweaks, such as for hiding system applets, customizing the Windows firewall, and more. All in all, it's an excellent tool for anyone who wants to get more out of Windows 7.
Note: The vendor also offers a free version of EnhanceMySe7en, which by the developer's estimate has only about 60 percent of the features of the paid version. The paid version includes features such as performance, network, and security tweaks; plus hard drive optimization.