Depp, followed by George Clooney, topped the magazine's 14th annual survey of Hollywood's best and worst signers. The "Pirates of the Caribbean" star also was rated best last year.
"Many stars become bad signers once fame and fortune hits, but not Depp. He's even signed autographs for crowds at the airport while carrying luggage," said Steve Cyrkin, editor and publisher of the Santa Ana, Calif.-based magazine.
As for Clooney, "he'll joke as he signs, and make fun of how he looks in photos he's handed to autograph," Cyrkin said.
When it comes to her moniker, however, Diaz gets a flunking grade.
"Cameron Diaz may be a talented actress, but she's persistently a terrible signer. Instead of just turning down a person's autograph request, she'll lecture them about how dumb autographs are," Cyrkin said.
Russell Crowe would have been named as the best of the worst but in recent months he has been much nicer to fans, Cyrkin said in a telephone interview Friday.
Cyrkin said the list, which appears in the magazine's June issue, was based on information from a professional autograph collector and an enthusiastic amateur who is a journalist.
"They're the guys who want to get five or 10 or 12 of everything but they do see people" and know the "track records" of the stars, he said.
"It's looking at the spirit of the way they sign," Cyrkin said. "It's how they treat their fans."
Here is the list of 10 best and 10 worst Hollywood autograph signers for 2006, according to the magazine:
1. Johnny Depp
2. George Clooney
3. Matt Damon
4. Al Pacino
5. Tom Cruise
6. Angelina Jolie
7. Elijah Wood
8. Brittany Murphy
9. Jack Nicholson
10. Clint Eastwood
1. Cameron Diaz
2. Bruce Willis
3. Demi Moore
4. Tobey Maguire
5. Alan Alda
6. Halle Berry
7. Winona Ryder
8. Teri Hatcher
9. Joaquin Phoenix
10. Russell Crowe