#1- Mega Man 2
#2- Mega Man 3
#3- Mega Man
#4- Mega Man 6
#5- ?
This one is really a toss up for me between 5 and 9. I have to go with Mega Man 9 though. I was just so impressed with the overall quality with that game. It's just so well polished, it's hard to go against. So I'll cast my vote for 9 while Tornado Man's song loops through my head.