I have never spent much time on Windows machines but I _love_ cmd-` on the Mac. I mean, I have a whole rant about how its ordering behavior changed on Lion for the worse but I love having windows grouped by application and picking the app I care about before picking the window I care about. I have never understood why so many people use a single chrome window for all of their tabs but I think it comes from not being experienced with cmd-`. For me, I group tabs in my browser by subject, most commonly, by google search query, and then I can close them all at once when I'm done with them.

I've actually started braking more websites out into their own fluid.app so that I can cmd-tab to them specifically. Jira, Github, Gmail (well, when I used gmail) all get their own app so I don't have to go hunting for that single tab in my browser, making my browser window management that much easier.

If you're interested in that, I pair fluid.app with choosy so that links open in the correct fluid browser.