Funny, this sounds like a good idea, but I'm quite happy with the exact opposite: I use rcmd[1]. I hold down the right command key and press the first letter of the window name to switch to it. I can override this dynamic mapping by pressing right command + option + <other key>, so I have an IM client on I, for example. It means I never have to remember/guess how command+tab works (although I had fewer issues with alt+tab on Windows)