Run conduit perpendicular to ceiling joists in garage
Sticking to the "running conduit" aspect... 

Must be attached/supported within 3 feet of each termination. Must be supported/attached no less than 10 feet apart along run. 

Given things that chew wires, I'd strongly suggest sticking to conduit the whole way. But if you want to you can have a juction box and change from wires in conduit to cable in the drywall. You CANNOT run wires that are not cable in drywall, and it's impractical to run cable in conduit. You CAN run conduit in drywall.