Any of the big 4 will be reliable. Hondas are known to be the most reliable, suzi's are the least, but they are all VERY GOOD. Gas milage depends on how you ride. But even with the most agressive riding style, the sort the will get you thrown in jail, you will still get high 20's. Highway cruises will get you 40's on almost any bike, with low 50's not being uncommon. If you opt for a smaller displacement bike like a GS500, ninja 250/500, you might have to worry about gas going bad in the tank before you get a chance to use it.