According to the American Library Association, here are the top ten most frequently challenged books of 2009:
Out of 460 challenges as reported to the Office for Intellectual Freedom
1. ttyl; ttfn; l8r, g8r (series), by Lauren Myracle
Reasons: drugs, nudity, offensive language, sexually explicit, unsuited to age group
2. And Tango Makes Three, by Peter Parnell and Justin Richardson
Reasons: homosexuality
3. The Perks of Being A Wallflower, by Stephen Chbosky
Reasons: anti-family, drugs, homosexuality, offensive language, religious viewpoint, sexually explicit, suicide, unsuited to age group
4. To Kill A Mockingbird, by Harper Lee
Reasons: offensive language, racism, unsuited to age group
5. Twilight (series) by Stephenie Meyer
Reasons: religious viewpoint, sexually explicit, unsuited to age group
6. Catcher in the Rye, by J.D. Salinger
Reasons: offensive language, sexually explicit, unsuited to age group
7. My Sister’s Keeper, by Jodi Picoult
Reasons: homosexuality, offensive language, religious viewpoint, sexism, sexually explicit, unsuited to age group, violence
8. The Earth, My Butt, and Other Big, Round Things, by Carolyn Mackler
Reasons: offensive language, sexually explicit, unsuited to age group
9. The Color Purple, by Alice Walker
Reasons: offensive language, sexually explicit, unsuited to age group
10. The Chocolate War, by Robert Cormier
Reasons: nudity, offensive language, sexually explicit, unsuited to age group
And here is a map of the book ban challenges: http://bannedbooksweek.org/Mapofbookcensorship.html