Interesting you should bring this up, I've been putting together a post for a while on my particular setup. I've got lots of shortcuts and workflow enhancements that I've carried with me (and refined) over the years and now implemented using tools like Mjolnir and BetterTouchTool. It's OS X specific, though, since that's my primary workstation OS.

A quick overview of my some of the things I've enhanced my coding workflow with:

• I use BetterTouchTool to configure gestures on my trackpad and keyboard for frequently used apps. I can hold either alt or cmd and then swipe 3 fingers up, left, right or down for one of 8 frequently used apps (which is either launched if its not running or otherwise raised to the foreground). I view most documentation (that which I can) through Dash, which I can raise with ctrl+alt+cmd+/. My terminal is always a cmd+alt+§ away.
• I use Mjolnir for window management with a custom script I threw together a while back, which divides my screen into 9 logical columns. I can then use ctrl+cmd and either left or right arrow to select a direction, followed by a 1-9 to select the number of columns the frontmost app should stretch, or 0 to fill the entire screen (without actually going fullscreen). I can also make window half the screen height by using ctrt+cmd and up or down arrow. This way I can throw windows around and put them in logical sections of my screen and maximise the space I have available to me.
• In my terminal use a custom script that opens any subdirectory in ~/Work in tmux (e.g. I just type tm foobar).
• I have lots of aliases for common things on the terminal, such as m to open the current directory or a given filename in TextMate, and an a alias for Atom.
• I also shorten a lot of common commands with aliases, such as docker-machine (dm), spring rails server (srs).
• I use zsh and zprezto as my shell, for which I've written my own modules for various tasks.
• I keep my dotfiles in a repository so I can keep track of them and share them between machines using rcm (though I am moving away from rcm and switching to ansible for lots of reasons).
• I use scm_breeze to simplify working with git on the command line for common operations. I also use SourceTree and its stree command line utility when I need a gui (reading long commits, histories, etc).
• I've also written a few packages for Atom that integrate various apps I use (such as iA Writer and SourceTree)

There's a ton more bits and pieces, but those are the major points.

The basic premise of what I do to enhance my workflow, is to reduce the number of brain cycles I need to do any given task - particularly the most frequent tasks. Switching between Terminal and my editor (currently Atom) and two browsers (one for browsing, one for dev) is probably my most frequent task, so all of those things are available with alt and 3 fingers up (Safari), down (Chrome), left (Atom). Xcode is actually on alt right, but I haven't done much iOS development lately. My terminal is ctrl+alt+cmd+§.

I don't have to think about which tab order the apps are to switch most efficiently between them, nor do I have to recognise icons, or even alt-tab in the first place. The shortcuts to launch those apps are embedded in my brain and they take almost zero thought to perform, and therefore have no impact on my general flow as I am coding, testing and such.