Latex means water-based. Do you mean using semi-gloss or satin instead of flat?
Or do mean using enamel (oil based) instead of latex?
I would go with satin latex myself...little or no shine, but nice and smooth...easy to clean (god forbid...it's a garage remember?)
Latex paints are great these days. The only reason to ever go with enamel nowadays is if you're painting over metal that the water-based latex will rust.
In order of shine/smooth: