If the Patriots somehow win the Super Bowl next month, I think virtually all conversation will be ended as to who the greatest QB of all-time is. If Brady wins a 4th ring, 8 seasons after winning his last one, in the era of free agency, parity, etc., I personally think that is a greater accomplishment than Bradshaw or Montana's 4 titles or anything pre-merger (Graham, Luckman, Tittle, Unitas) or early modern (Lombardi's Packers).
Along with that, Belichick (who already has a HOF resume) has to go down as one of the greatest not only coaches, but personnel guys as well.
Belichick took over in 2000, which was also his first draft. He ended up with the following drafts:
2001- Richard Seymour, Matt Light
2002- Daniel Graham, Deion Branch, Jarvis Green, David Givens
2003- Ty Warren, Eugene Wilson, Asante Samuel, Dan Koppen, Tully Banta-Cain
2004- Vince Wilfork, Ben Watson
2005- Logan Mankins, Ellis Hobbs, Nick Kaczur, James Sanders, Matt Cassel
2006- Stephen Gostowski, Ryan O'Callaghan (this was the Maroney-Chad Jackson year, bad draft)
2007- Brandon Meriweather (nothing else came from this, worst draft of Bill's NE era)
2008- Jerod Mayo, Matthew Slater (this was the "fix the secondary draft, Wilhite, Wheatley) Crable never got healthy
2009- Pat Chung, Ron Brace, Darius Butler, Sebastian Vollmer, Brandon Tate, Myron Pryor, Julian Edelman
2010- Devin McCourty, Rob Gronkowski, Jermaine Cunningham, Brandon Spikes, Aaron Hernandez, Zoltan Mesko, Brandon Deaderick
2011- Nate Solder, Ras-I Dowling, Shane Vereen, Stevan Ridley, Ryan Mallett, Marcus Cannon
2012- Chandler Jones, Donta Hightower, Tavon Wilson, Jake Bequette, Nate Ebner, Alfonzo Dennard
That first chunk (along with what Bill inherited) won this team 3 Super Bowls. The middle chunk were lean years. Those guys helped the Pats reach another Super Bowl. And this last chunk appeared in another Super Bowl last year, with a chance to get back and win another one this year. Overall, Belichick has drafted very well and lots of teams now copy the Pats model of not paying older guys, stockpiling picks, staying out of free agency for the most part, and trading down in drafts to build depth. If Belichick & Brady win another ring this year, they are the best coach-Qb combo in history beyond a doubt, they are already in the discussion but that would clinch it I think.