There's only one historical novel among the top 15:
#13 - A Good Woman, Danielle Steel (636,375 copies)
The remainder of the top spots were taken by thrillers and mysteries, Edgar Sawtelle, Stephenie Meyer's The Host, and an inspirational holiday novel called The Christmas Sweater that I've never heard of. Clearly I am out of the loop.
Other bestselling historical novels in hardcover, all with sales from 300,000 to 100,000 copies, are listed in descending order:
The Guernsey Literary and Potato Peel Pie Society, Mary Ann Shaffer and Annie Barrows
A Mercy, Toni Morrison
The Given Day, Dennis Lehane
The Other Queen, Philippa Gregory
People of the Book, Geraldine Brooks
The Fire, Katherine Neville
World Without End, Ken Follett
Christ the Lord: The Road to Cana, Anne Rice
The Steel Wave, Jeff Shaara
The Enchantress of Florence, Salman Rushdie
Days of Infamy, Newt Gingrich and William R. Fortschen
I've read three of these (the Shaffer/Barrows, Gregory, and Brooks). How many have you read?
It's worth noting that of the titles above, many (Neville, Follett, Rice, Shaara, and the Gingrich/Fortschen) were highly anticipated sequels to bestselling novels from previous years. The Shaffer/Barrows is the only one that can be considered a debut of sorts, though Barrows has previously written children's books.
Follett's World Without End was #19 on last year's list, and it also sold 116,000+ copies in 2008 (plus 521,000+ copies in trade paperback in '08). No other titles duplicate between the '08 and '07 hardcover lists, though on the trade paperback list for '08 you'll find many familiar favorites like Water for Elephants, Atonement, Loving Frank, Pillars of the Earth, and The Other Boleyn Girl (movie tie-in edition), listed in descending order of sales.