I am basing my list on who I would want to lead my team at QB right now.
The 3 rookies all played fantastic. It was incredible to watch those guys play this year. RG3 was very effective in large part because of his ability to run and the zone read option. Lets see how that plays out for the next couple of years. I don't think it is a long term solution to offense. Defenses will start to have an answer for it. If he continues to play at the level he did this year he will jump Flacco. Luck threw a ton of interceptions this year. Granted, that was also attributable to being behind in games and having to throw more than some of the other guys. He did throw just about as many picks as TDs though. Not turning the football over is huge and as he gets older and more experienced I would expect this to change. When it does, he will probably move ahead of Flacco.
Romo just doesn't get the job done. He has had a TON of late game fall aparts in the last couple seasons. Rivers hasn't been able to win at all in SD for the last couple of seasons.
Running through Denver and NE like Flacco has this postseason is making his case for a top 8 QB a lot stronger. He went head to head with 2 of the best QBs in the history of the NFL and completely outplayed both of them.