Obviously it's personal, but the main issue I've always had with Alt-Tab is that as soon as you have more than 2 windows, getting to a specific application is now something you have to think about (or hit key, look, possibly hit key again). Since I'm often doing web development, I usually have a terminal open, an editor, and a web browser. Except for terminals, I pretty much always have everything full screen - the benefit is that Super-1 gets me to terminal(s), Super-2 gets me to my editor, and Super-3 gets me to the browser.
This is also true in Ubuntu's Unity, but after trying to use it, a minor issue drove my crazy: if you switch to one that isn't open it will open the application. So if I accidentally Super-4'd (which I didn't think I did, but after trying to use Unity for a while, I'd do it at least several times a day), it would start whatever the 4th application was. And then you have to deal with it showing up a fraction of a second later. I don't want switching and starting applications to be the same action, because switching should _always_ be extremely fast. If there was a way to make it only switch if it was open, then this would be a viable option for at least my workflow.
Thank you for reminding me. It's actually even better than that. Let's say your taskbar looks like this:
(1) Browser: pinned and now open (1 tab only).
(2) Windows Explorer: pinned, open, several windows.
(3) Windows media player, pinned, closed.
(4) Notepad: not pinned, but open.
Win+1 will bring the browser to the front, unless it's already there, in which case it will minimize it.
Win+2 will bring a Windows Explorer window to the front, and if you keep pressing it will cycle between them.
I actually find that _worse_ than what the parent described. If I hit Win+1, I want to see the browser provided that it's open. I don't want the state of the system prior to hitting that to have any effect on it. If I accidentally hit Win+1 twice, it seems that I would end up minimizing the browser. At least for me, the primary value that tiling window managers provide (even though it has little to do with tiling!) is idempotency.
I find Win + Left/Right (makes the program use left or right half of screen, Win+Up for fullscreen) the best news in Win7+.
This saves so much time and makes me hate all programs that do not support it fully.
I've come down to just using Terminator terminal emulator[1] (which allows you to open multiple sessions in the same window with a CTRL+SHIFT+E or CTRL+SHIFT+O) and a web browser. I used to care about which desktop I used (KDE or Gnome, etc) and how it was setup... but lately that just hasn't bothered me. As long as I can have 3-4 terminals open in the same window, and some browser, I'm productive.
I work this in OS X by using Alfred (Spotlight would work too). It's just Cmd+space to bring up the search bar and then another another letter or 2 (v = MacVim) and hitting Enter to switch.
