This'll be a short post, but there are many things I love about Windows 7, and many things I really like, but I've just discovered something that you might not have heard about yet: in Windows Explorer, you can now tab to complete the path in the address bar. For example, in the path below, I can type "Of" and then hit tab and it will automatically complete "Office" followed by the next backward slash, ready for me to continue on down the path.
This might not seem like a big deal, but see how much time it saves navigating to "C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Temporary ASP.NET Files". And yes, that's if you haven't already set up Executor/Launchy/Enso (note: does not work on x64)/Etc. to have a shortcut already to that particular location. However, it's even better than those launchy applications in that it's a) in Explorer already, b) it allows you to sometimes tab, sometimes type, sometimes arrow down to a selection, and c) hitting enter opens the current directory, but then you can go right back up with alt-d to the address bar and continue on again. If you use any of the above launchy-type applications, you'll know what I'm talking about. If you're not yet using one of them, hello?!? (and yes, while the new-in-Vista start button is an improvement, it's still not near as feature complete).
Another handy thing that I needed a third party app for before is the now-native "Copy as path" option for files (although you need to shift-f10 to open menu, or shift-left click to get it to show):