Dunno the difference between the order, probably marketing? As far as which crank set number is best...depends on several factors, like wheel size, cog spread in the rear, crank arm length, etc. I would suggest reading Sheldon Brown's treatise on gearing and play with his gear ratio calculator a bit to get a feel for it. FWIW I have different bikes and the front chainwheel combo's range from a 22/32/42 to a 28/42/52 depending on the bike and it's use.

Aaron