Interesting question. Not sure I can agree with your list, as it really is a compilation of the coaches who happen to have the best records this season, YTD. Great coaches have bad years, and blind squirrels occasionally find nuts. The best ones build bad teams into great teams, then sustain that greatness.
Based on the body of their respective work, I'd personally not rank Andy Reid in the top five, maybe not even top ten. Much like Jeff Fisher, his resume says he's great at building mediocre to good teams, but not a getting them to the next level. I could be biased against him being in the Philly area, and watching him for 14 seasons.
Payton certainly belongs, as was evidenced by how poorly his team performed when he wasn't on the sideline, and how they rebounded once he was. It takes a special kind of greatness to take such a moribund and snakebitten franchise to the promised land.
Any list of the best coaches is incomplete without Belichick, like him or not.
Tom Coughlin needs to be on the list, despite this year's debacle.
John Fox is a good coach, having taken Carolina to a SB and close to another. He looks like a genius, thought, with Peyton.
Pagano looks great right now, but Arians did a helluva great job with that team last year. Perhaps more impressive due to the roster overhaul and rookie QB.
Pete has certainly done a wonderful job in 3.5 seasons. If he gets them to a SB or two, he will solidify his greatness. He's trending into the top 5, but might still have to prove a few things. Same goes for Jim Harbaugh.
Top five is rarefied air. If I had to rank them now, I'd go:
1. Bill Belichick
2. Tom Coughlin
3. Sean Payton
4. Mike McCarthy
5. John Harbaugh
Honorable mention or trending upward:
Pete
Jim Harbaugh
John Fox
Chuch Pagano
Overrated, IMHO:
Mike Tomlin (two rings can't be argued, but seems to be taking a once-great team steadily downward)
Andy Reid (having a great season, but history says he will fall short)
Jeff Fisher (highly respected and well-liked, but has a history of mediocrity and unsustained success)
Mike Shanahan (was great with a guy named Elway, Meh ever since)