The novelization of the new Star Wars movie by R.A. Salvatore, just released in the US and UK, has already cracked Amazon UK's hardcover fiction list, at #10.
Presumably as a result of his signing at Cody's Books in Berkeley on April 19, Kim Stanley Robinson's The Years of Rice and Salt places #6 on this week's San Francisco Chronicle list.
Stephen King's Everything's Eventual slips just a bit this week, but is still the best/broadest-selling genre book on this week's chart. In the UK, David Gemmell's Stormrider ranks #7 on both lists, just like last week.
In one of those odd quirks (mistakes?) of bestsellers lists, Ray Bradbury's Fahrenheit 451 placed #1 on LAT paperback list 2 weeks ago (it's the pick for the city-wide reading program in April), was not on the list at all 1 week ago, but is back at #2 this week.
This table isn't tracking Spider-Man books, but at least 3 tie-ins to the forthcoming film are on this week's New York Times lists this week.