When people start debating which schemes are best, you'll see the topic answered in many different ways from many different points of view. Inevitably, the arguments finish with talent. It is said the best offense is one that ultimately best suits the available talent.
While true (duh), I find that way of looking at things rather boring.
I'm a system guy, so that's the way I tend to look at this particular debate. Basically, I think the best offenses are ones that afford the most solutions to any problems presented by a defense.
Flexibility is paramount. The system must be mechanically flexible in how it operates, and it must also be flexible in how it adapts to personnel changes.
In this view of tactics, the following systems most completely encompass the above requirements:
I hesitate to list Shotgun because of how dependent it can be on dynamic talent at the QB and RB positions. The running game can be extremely limited in every facet depending on personnel and approach. Are you Oregon or Hawaii? The term shotgun is too generic now.