Right, there's this type of application:window divide in OS X which is really nice. There's two levels of window switching, between-applications and between-app-windows that beats the pants off of the "traditional" taskbar model seen in XP and most Linux distros. Mixing windows and applications in alt-tab generally just causes tons of problems in trying to guess which is on top of the stack, not to mention that application switching screws up window switching.
I hear Windows 7's taskbar is much more dock-like, which would be a serious benefit, I get actual headaches from working with XP at work 9 hours a day.
OS X which is really nice... beats the pants off of the "traditional" taskbar model seen in XP and most Linux distros
That's a matter of personal preference. I personally loathe the way OSX forces me to decide between Apple-Tab vs Apple-Tilde. I just want to switch.
But to be fair, it's absolutely annoying and stupid Microsoft Office applications decide they need two entries in the stack. For example, why does having n Excel workbooks open require n+1 entries? No other applications do that as far as I know.
I hear Windows 7's taskbar is much more dock-like, which would be a serious benefit, I get actual headaches from working with XP at work 9 hours a day.