Of all the things that can go wrong with a job, I think feeling as if you're not growing is one of the most dangerous. The market for your talents is changing every day, and unless you are evolving, too, you run the risk of becoming as obsolete as punch cards in a software world. Be vigilant if you feel you are not learning anything and your current employer is paying you more than anyone else would. That means it is definitely time to run, not walk, toward opportunities for building new skills. (A boss looking to cut workers will always target the ones who cost him more than their talents warrant.)
You might register for technology courses or simply ask your current employer for new responsibilities. Concentrate on shoring up an area you feel is your biggest weakness or building on your second-greatest strength. (You've probably automatically refined your strongest suit because it's something you love to do.)