I haven’t read The Road yet, but McCarthy’s No Country For Old Men is a page-turner. It does take a few pages to get used to the non-standard punctuation, but then the plot heats up and you won’t care.
Zelazny’s Lord of Light got me through my most recent plane flight, though I doubt it’ll last a full 18 hours. There is an omnibus edition of the Amber chronicles available, as well, if you haven’t read them yet - they’re a bit more straightforward, and have kind of a Gilbert and Sullivan feel to them. The book is trade paper size but quite long. Also in the “if you haven’t already,” the George R.R. Martin Song of Ice and Fire volumes certainly qualify on “length.”
John Varley’s Mammoth is fun, doesn’t take itself too seriously, and screams “make me a movie!”, but may be too short. Starts with an unearthed ice man wearing a wrist watch and goes from there. Alastair Reynolds Pushing Ice is longer, and it has a nice twist towards the end; his Chasm City has a wonderful setting of a ruined-city-that-was.
Charlie Stross, Glasshouse and Singularity Sky. Now both available in pocket paperback.
There’s a collection of James Tiptree Jr. short stories out now, And Her Smoke Rose Up Forever. Trade paper size, unfortunately, but great for quick bites. Another individually quick but long-ish and fun anthology is Semiotext(e) SF, which captures a certain moment of late 80s futurism and includes William Gibson’s “Hippie Hat Brain Parasite.” (Regrettably, the title is the best part of that story.)
Zadie Smith, White Teeth or The Autograph Man. I liked On Beauty, as well, but it was weaker than the other two.
Michael Chabon, The Yiddish Policeman’s Union. Unfortunately it appears to only be in hardback, which is a downside. Still, I couldn’t put it down. More put-down-able, but still good, is Roth’s The Plot Against America, which focuses on a world where Lindberg ran to keep us out of WWII. For a slightly different alternate present, S.M. Stirling’s Conquistador has a gateway between the Berkeley hills and an alternate world where the European conquest of the Americas never happened.