I like Macs (for full computer disclosure, I have had three Macs, two PCs from Dell before the Macs and then an Apple IIGS and an Apple II+ before the PCs) but I have always hated the way that Alt-Tab switches between open applications instead of between open windows the way Windows does it.
I finally got fed up with using the mouse to switch between windows earlier today and did some Googling and found someone else complaining about the same thing. I read through the comments and at the very bottom found the solution.
Alt+` will switch between open windows in the application you are current using. Now I can easily check on Chatzilla while I’m using Firefox and that makes me happy.
Note: I also just came across Witch and this does a good job of allowing you to see and switch to any open window (even one that is minimized).