I'm starting Gore. He has all 4 Niner TDs so far this season, including two vs. the Cards when he couldn't get anything on the ground.
When the Niners get into the redzone, Gore is their number one target on the ground and in the air.
That being said, McGahee has had a great season so far, and there's no reason to believe it will stop vs. pathetic Cleveland.
The smart move would be McGahee over Gore, but I enjoy having the extra incentive to cheer my arse off for the Niners and Gore.