It does sound like a starter starting to fail. If it gets worse, and you can't start, hit it with a hammer and it should start.

Also you may have a weak or leaky fuel pump or a losing presure in the line as a seperate problem? When you first go to start the car, turn the key to run, wait for 2-3 seconds, then crank it (if your starter will let you). What you are doing is letting the fuel pump pressurize the line and it should start easier. But then again, clunking out sounds like a throtle problem?