Looking to tweak Windows 7 and squeeze out a little more speed? You're in luck, as the unofficial Windows 7 Forums provides nineteen ways to make that tasty new OS run faster. The helpful list includes a few obvious tips like boosting your RAM to 3 or 4 GB, switch to solid state drives, and keep the system drivers updated.
One of the tips found on the list is to install the correct version of Windows 7. Consumers with a high-end PC with over 3 GB of RAM crammed inside should be using the 64-bit version "in most cases," as the 32-bit version won't take advantage of memory just over the 3 GB limit. There's also a thorough explanation found here that offers a more detailed reason as to why you should use the 32-bit or 64-bit version.
The list also provides other obvious ways to speed up the OS, however we've known about these since the days of Windows 95/98/98SE/XP: defrag the hard drive(s), disable those pesky, unwanted startup applications (Real Player and QuickTime as usual suspects), and disable unwanted services. You should also uninstall unnecessary software, clean up old files, and run periodic anti-spyware scans... no-brainer stuff there.
Unfortunately, this list of tips doesn't really provide anything utterly bewildering like "change this registry key" or "do this to speed up that." The list does suggest that you disable gadgets, choose a high performance plan, disable search indexing, and make use of keyboard shortcuts. The list also says that you should change Windows 7 visual effects, perhaps even disable all the effects to get the maximum boost.