Painting - Garage Floor Painting

What is the best/most durable paint to use on a garage floor? Will a two part epoxy hold up to oil/gas/salt or should I use polyurethane? What type of surface preparation is necessary? What is easiest to apply and maintain?

DSerrage, To prep concrete do a basic cleaning if needed with any good detergent and etch it when dry with muriatic acid according to label directons. I doubt two part epoxy would last longer than a high quality floor urathane and sure would dread having to go with two part from now on because nothing else will bond to it. The only real difference in using two part is the mixing but but brushes and roller cover are always thrown away when finished because it is not practical to wash. From what I've seen over the years given that a floor job is done right to start with is the key to it lasting is to keep it fairly clean as you go along. Many times people wait a year or two to do a good cleaning and the driving and such on the grit roughs up the surface and it will not come clean....Mike