Best outdoor paint brands for wood siding?

Just moved into our first home, our garage is detached and has old wood siding that's in fairly good condition. The paint is a little rough for wear and I really want to paint it another color with some big white simple flowers (a shed in our old town had this and I loved it so much). That said, what paint brands and primers would you guys suggest? Also, I think it'd be wise to sand it prior, but I'm not sure, thoughts?