I'd say the Saints with the Cardinals playbook. They have a fleet of receiving options (Shockey, Colston, Henderson, Meachem, Moore) that all provide different strengths (speed, jump ball, possession). Drew Brees can make every throw and can scramble well enough to handle broken down plays. The oline is solid enough to stop most pressure, but I admit it's not spectacular.
They have a good versatile fullback in Evans and 2 RBs (Thomas, Evans) that balance each other out very well. If I had just one complaint with the native NO playbook, it's that I can't find enough quick passes.
The number and range of options at each position allows you to force defenses to declare their intention through formation and personnel group options.
Honorable mentions:
-Chargers for 2 RBs and Gates with solid o-line
-Panthers if you just play 2-man ball with Williams and Smith. Easiest offense to learn.
-Eagles if you can spread the field and balance with Westbrook
-Vikings if you just cheese and run AP on backside screen 40 times a game.
-Pats in spread formation are hard to beat because Oline can stop just about any blitz.
-Giants if you are a skilled running player.
$.02 deposited.