One slightly confusing clearance is when you're "cleared to takeoff cleared to land" when you're sitting on the runway. By the time you've got round the circuit, you're thinking to yourself "did he clear me to land?"
I agree its good airmanship to tell the controller what you're doing. If I'm cleared for the option but decide I want to make a full stop, I'll tell the controller and he / she'll then issue a 'cleared to land'...
cheers
EA