Brees is a different sort of cat... He has the stats and moderate post season success to be ranked highly... And it's a bonus to his credit that he took down manning in what was arguably his best super bowl performance...
He also lacked the physical attributes many other qbs of this era enjoy... ie he's short... Pfr has him listed at 6 feet even... The guy running the physical that day must have let him keep his sneakers on when measuring his height...
But what gets me about Brees is he never really took control of that division... Up and down ... Had a good run in 09, 10 and 11... But after that, back to the .500 mark... Injuries not withstanding, those were some talented teams he could never get over the hump...
Top ten of his era, but top 5? I'd have to really look at the other guys before deciding if he ranks that high... As other have pointed out, there was a lot of stat padding in some pretty lean years record wise in the big easy...