Python. I'm sure people will fill in the scripting language of your choice, but knowing at least one is a real time saver. I have lost count of the hours and hours and hours of drudgery I have saved because of being able to fire up a script in short order.Life is good when you can make a 2 hour task take several minutes :-) Especially if that task is something you have to do on a consistent basis

For life in general, exercise has been good. I'm in crappy shape now, but getting back on the wagon. Being in some semblance of shape does wonders for your health and well being. And strength training in particular makes you less of a victim in many life circumstances, like having your snack stuck in the vending machine or moving furniture. The downside, obviously, is that you get asked by people to tip vending machines and move couches...