Well, Dewey (and Strom Thurmond), Stevenson (twice), Nixon (wouldn't really count him since he became President later), Goldwater, Humphrey (and Wallace! also VP so a little more high-profile), McGovern, Ford (was POTUS so doesn't really count), etc. But yeah, no doubt the general populace wouldn't know this. I just thought you meant by "remembered" as in history text books or things of that nature. I don't really expect average Joe in 75 years to remember John McCain, though McCain is more likely to be remembered in such a way than other failed nominees.
2008 was a momentous and historical election so McCain is much more likely to be remembered because of his nomination because of this. He's also an esteemed veteran who was tortured in Vietnam - yeah, I think he'll be remembered. People like Romney, Kerry, Dole - maybe not because those elections weren't necessarily important historically.
As far as the general populace goes? The "general populace" would probably have trouble naming presidents - not just failed nominees - that served prior to their birth. Maybe pre-FDR would be a better time frame here, I guess, because I would hope people could name the post-war presidents easily.