Post-ride nutrition, carbs or protein?

So I go for a little ride, maybe 20 miles, and when I get home I'm vexed with the challenge of what to eat.  Do I drink in protein shake so that it can be rapidly absorbed and help build muscle?  Do I eat copious amounts of carbs to replenish muscle glycogen?

Then I read "When the glycogen depletes entirely, the body has no more fuel and instead burns fat, resulting in a surge of fatigue and a performance collapse" and I know I want to lose fat!  So if I want to lose fat to I try and limit my carb intake and therefore glycogen levels?

One thing is for sure, a little information is a dangerous thing...