I have to admit I never thought of books as a Rushmore, but why not?
Moving back to sports again, because it's a favorite of mine.
Mt Rushmore of NFL QBs
To me the answer depends on the context. Over all? At their peak? Given the same quality of team/coaching? I'm always noting that I think Brady is an all time great, but that his back ups looked like potential NFL stars whenever he went down and ordinary when they cashed that in elsewhere. For that reason I'll take Peyton in a close one between the two, trading Tom's hardware for Peyton's ability to make good players look better than they were. I'm going to split the Mt. Rushmores between 1980 and prior. Montana's ascension is the mark for the second grouping.
Montana: 40+k yds, 63% comp., 92 rating. The GOAT. Perfect in SBs, never threw a pick in one. Could have as easily won one or two in the two years he was exiled to KC. Beat eventual SB winner and usurper Steve Young in a head to head contest utilizing that lesser Chiefs team.
Manning: 70k yds, 65% comp., 96.5 rating. And that's with the last couple of year ungluing factored in. The best regular season qb is the knock, but until his rapid decline in the last year or so he was actually better, statistically, than Brady in both the regular and post season. Rallied to beat his rival with a broken instrument for a last hurrah to take that defense dominated Broncos to the SB where they rewarded him with a ring. Won ten and eleven games before the neck injury with a team that won two without him. Put up the same numbers in multiple systems.
Brady: 61+k yds, 64% comp., 97.2 rating. A winner's winner. Best system qb of all time. Athletic, driven. Great at rallying the troops late.
Brees: 66k yds, 67% comp., 94 rating. Has been ridiculously good on mostly not so good teams and took one that didn't belong there to a SB and a win. Unless Rodgers or Ben mount a challenge late, which is possible, I think Brees is the most underrated qb in modern history and that will be course corrected when the Brady/Manning glare recedes a bit.
Hon. Men.:
Marino, best pure passer I've ever seen. Unbelievable release. Too good to give so-so teams draft picks and that was that. Won't crack the list now.
Elway, largely on the talent you can't deny and what he managed to do when the tank was empty.
Favre, the gunslinger who showed at 40 that there was untapped greatness that might have seen him solidly on Rushmore if he'd played within the game more early. You can argue it, but I don't see him knocking anyone out of the list.
Rodgers, who I suspect is Brady plus but on the wrong team. Still time to pad his resume and challenge for the list with Elway.
Roethlisberger, who just doesn't get the love he deserves for what he's done, and a lot of that goes to his off field antics and personality and a name no one can spell outside of Pittsburgh. While he's flirting with retirement now like Favre late, he is also in a position to flirt with the list if his team gets hot for a couple, which is possible.
Warner, too thin and inconsistent a resume, but if he'd been able to start early? Who knows. A great big game player who was a couple of defensive plays away from being the first qb to take two teams to SBs and win.
Rushmore of pre 1980 QBs
Unitas, terrific winner and the best coach on the field until Peyton.
Starr, a lot like Brady. Got it done. Ran the system to perfection.
Graham, revolutionized play at the position and had legs to spare.
Bradshaw, the forerunner of Favre. Physical, confident, and made big plays for both teams on a regular basis.
Hon. Men. :
Staubach, who led the league in passing four times, won two SBs and had a few years of national service taken from his potential. If he'd been able to play then who knows?
Tarkenton, the most effective running qb the game has seen, except for Young.
Baugh.