This is one of those hacks that saves me 200ms per use, but that I use at least 50 times per day. It took me 5 minutes to make, so I broke even after a month. Not a bad return rate.
I spend half my day with a Sublime Text window on one monitor and a Chrome window on the other, making tiny changes to a CSS or JS or HTML file and then reloading. I got tired of having to command-tab or click on my Chrome window to reload, so I made this applescript to reload the active tab in Chrome:
tell application "Google Chrome" to reload active tab of window 0
Then I bound that script to the keyboard shortcut ⌘-Shift-R (I used Alfred, but you could use whatever other keyboard shortcut thing you want). Now I can reload my Chrome tab no matter what app's in the foreground.
Here's my Alfred workflow if you want it.