I don't read fiction but McCarthy is one of the more highly regarded fiction writers around.

Indeed. He won the Pulitzer prize for the Road, his most recent novel, which has also been made into a film, due for release in November.

The well regarded movie bad book I was thinking about was No Country for Old Men. Roeper thought nothing of the book, but loved the movie. Is Cormac McCarthy any good? I know his last book was well reviewed, but I haven't heard anything good about him otherwise.

No Country for Old Men is a good book.

Blood Meridian is a ####### GREAT book. I intend to read The Road sometime soon.

Cormac McCarthy is one of America's greatest living writers. However, No Country For Old Men is second-rate McCarthy. Blood Meridian, Suttree, and All The Pretty Horses are where you get your McCarthy fix.

As for bad books making great movies, Jaws has got to be #1 on the list. It's a terrible book, just terrible, with a lame adultery subplot, comically heavy-handed attempts at echoing Moby Dick, and the most wooden writing style imaginable. What Spielberg did with the source material was pure magic.

As for great musicians who are great actors, my list really consists of two: Dwight Yoakam and David Bowie. Bowie began his career in the theater before he turned to music, and regularly went back to it (his turn as John Merrick in The Elephant Man on Broadway is celebrated). He's a very good actor, and never better than in The Man Who Fell To Earth. Which just so happened to coincidentally be filmed in tandem with his greatest album, Station To Station.

Cormac McCarthy is one of America's greatest living writers.

As good as DeLillo? As good as McGuane?

DeLillo has fallen off (and his peak was never as high as many have claimed...White Noise in particular is overrated puckish nonsense). Thomas McGuane? Second-tier, if I'm being generous. Pynchon is still the best (with only Vineland to his name as a bomb), but in an alternate universe where Gaddis is still alive I might run him close to the top.

Either way, I never claimed McCarthy as THE greatest living American writer, just among the top tier.

As for a (dead) underrated writer, how about pulp fiction author Jim Thompson? The Getaway is such an oddly compelling fusion of nihilistic noir and Kafkaesque grotesque that it's always stayed with me. Sure, a writer of potboilers in the end...but memorable potboilers.

Cormac McCarthy is an extraordinary writer. One of the finest alive.

It was based on an Upton Sinclair book, if I remember correctly. I haven't read it, and I hadn't heard of it before the movie, but I assume it wasn't too obscure (or too bad) if Sinclair wrote it.

I don't think this is a good assumption. Sinclair would be forgotten today were it not for The Jungle and his work as a political activist. He wrote literally hundreds of books that have fallen out of print. I don't think you can assume a consistent standard of quality. Oil! is itself out of print except in a movie tie-in edition.

Others who come to mind who have done both (no comment on their respective worthiness intended):

Joe Strummer
Billie Piper
Deborah Harry
Julie Delpy
Mare Winningham
Glenn Frey
J.D. Souther
Lulu
Ringo Starr
Juliette Lewis
Phil Collins
James Taylor
Shane MacGowan
Neil Innes
David Essex

Nobody mentioned Lee Marvin who had a number 1 hit in the UK with his tender version of "Wanderin Star"?