With the population changes in 1.1, morale is waaaaaaay too good right now. Keeping your morale at 100% on a colony doubles your growth rate, and taking morale +20% and populists gives you +40% morale, and this lets you crank up the taxes to about 45% and keep all your planets at 100% morale. I think the best thing would be to remove the morale bonus on population growth, let morale strictly influence taxes. Having it effect both your population AND your economy is just way too much for one stat to do IMO.
In the mean time, if your not taking as much morale as you can get, your really shooting yourself in the foot. That 40% morale is like +50% econ and +50% pop growth rolled into one. Of course, go for the morale resources asap as well. The AI on intelligent knows this as well. In one game it built one colony ship and then grabbed a morale resource by its home planet.