But for me middlebrow signifies stuff that has at least some pretentions toward art status, respectability, critical approval and so forth, wheares middle-of-the-road is more stuff that seems to be deliberately unimaginative and unexciting, the appeal is that it's something comforting and familiar.
I was going to say... what about stuff that is just blandly, safely innoffensive... not trash... but not going for any depth or artistic value? So Middle-of-the-Road would be: Foo Fighters, Oprah, Friends, Sting, U2 (though I guess they, as much as I hate to admit, weren't complete shit at one point)...
and good Middle-Brow (to mine eyes) would then be; The Beatles, Fleetwood Mac, Daft Punk, Air, Beck, Stevie Wonder, hell - all Soul, Pink Floyd, M83, the Cure, Prince, Depeche Mode, anything Jim Henson, Star Wars IV-VI (yep, UNTOUCHABLE

), LOTR (hey, I like it :slanted

, Lost...
mid-tier Middle-Brow; hmmm... Nirvana, Radiohead, CSN&Y, Spike Jonze, a few John Hughes films, a couple Wes Anderson films
shit-tier Middle-Brow: Tool, the Mars Volta, Muse, Juno, Little Miss Sunshine
what about stuff that doesn't really aim for or end up initially in the Middle-Brow, but turn into sacred cows/critical darlings/cult influences... Led Zeppelin, Kraftwerk, Velvet Underground, Black Sabbath, David Bowie, etc?
what am I saying, of
course that stuff is middle brow.