There's just one feature I missed when I switched to Mac OS X. Windows 7 shows previews of open windows when you point your mouse at an application. I found an inexpensive application that adds this to the Mac; here's how to set it up effectively. It does require 10.6 or higher to run.First of all, download the DockView application from Kapeli. There's a free trial available. Just copy it into your Applications folder and run it. It will put up a menu that you can use to configure and manage the program. It seems to work pretty well by default, but there are some annoyances that can be easily fixed. The window previews will display in both the Dock and in the Application Switcher (Cmd+Tab) by putting the pointer over the application icon.
I keep my Dock on the left side and the window previews were getting positioned far away from the Dock. To fix this, change the 'Distance from Dock' setting in the DockView preferences. I recommend using the lowest value, but play around with it to find a comfortable setting. While you're there, you can change the window width and height as well, the default previews are huge.
I also experienced issues with window previews not showing for some applications. To fix that, go to the Filters tab in the preferences and try different filters for the application you have a problem with. If you're also using TotalFinder, there is a special filter for it.
Apart from this, it works quite well. Check out the Spaces tab if you use Spaces.
[crarko adds: I tested this, and it works as described. It's kind of a cool effect. Maybe I'll switch to Windows 7. OK, maybe not.]

