At home I use Linux (Fedora 19 running Gnome3 presently), while at work I have to use Windows 7. I have two screens in both environments. On Linux, I use alt-tab to switch through running applications across two screens, which works very well for me and has basically become muscle memory. On Windows, this is horribly broken in comparison: even when I have an application maximized on both screens, alt-tab often results in one screen or another being minimized right back to the desktop, creating a horrible jarring experience.
I find this so distracting in fact that I have to remind myself not to alt-tab while working on Windows 7 and two screens.
After researching this problem I discovered VistaSwitcher, which is free to use and solves the minimize to desktop issue I described, while also providing a much more plesant and stable experience. Well worth a look it you find yourself in a Windows slum.
Updated 2023 : note that the above post was originally published in 2013 and may be outdated, but is left here for archival purposes. I have fixed the broken link to VistaSwitcher, which is now called All-Tab Terminator.