A couple days back I stumbled upon a KDE 4 feature. Looks like KDE would let us use the Run dialog box (which is activated by pressing Alt+F2 from any application) to switch between open windows. I am the kind that has a lot of windows open all the time. Sometimes it might be easier/faster to type few letters of a window title to switch to it, and this feature does exactly the same.
I type "mail" on the Run dialog box and the options I have include commands available on the system (the "mail" command), apps like KMail, my quick launch shortcuts (Gmail, manki.in and Mail), and currently open Gmail Inbox. While this feature really is super cool, it would be even better if individual Chrome tabs are searchable like this. Well, that will also happen some day :)