Loose powder is your at-home, stationary powder. It provides more coverage than pressed powder, especially if used with a velour powder puff, and is quite economical.
Since loose powder can get messy in transit and is bulky, pressed powder is the mobile powder the one to take with you during the day for touch-ups and when you are on the road.
Your pressed-powder compact is probably one of the only makeup items you'll use in public, so choose a compact you really like. There are endless varieties from vintage silver or gold to fancy jeweled compacts to modern brushed-stainless steel and plain matte black.