Someone has made a list of the "100 Most Exotic / Rare / Different Voices" that has been floating around the internet. The list is claimed to be from Billboard Magazine, but I don't think it is. (Cyndi Lauper is listed twice, names are mis-spelled, etc.)
Either way the list has Hilary Duff at #10. While even the biggest Hilary fans can admit that she doesn't have the strongest voice in the world, most fans think that her voice is somewhat unique. So her place on a list like this would be warranted in my opinion... but it doesn't really matter because this list was probably completely made up.
1- Ashley Tisdale
2- Amy Winehouse
3- Amy Lee
4- Tarja Turunen
5- Savannah Outen
6- JoJo
7- Ne-Yo
8- Mariah Carey
9- Kelly Clarkson
10- Hilary Duff
11- Nelly Furtado
12 - Michael Jackson
13 - Leona Lewis
14 - Cyndi Lauper
15 - Jordin Sparks
16 - Shakira
17 - Christina Aguilera
18 - Justin Timberlake
19 - BoA Kwon
20 - Rihanna
21 - Mary J.Blige
22 - Anahн
23 - Toni Braxton
24 - Sarah Brightman
25 - James Blunt
26 - Whitney Houston
27 - Beyoncй
28 - Ciara
29 - John Mayer
30 - Belinda
31 - Gwen Stefani
32 - Nickelback
33 - Madonna
34 - Britney Spears
35 - Celine Dion
36 - Robbie Willians
37 - Jessica Simpson
38 - Thalнa
39 - Jennifer Lopez
40 - Carrie Underwood
41 - T.Pain
42 - Katharine McPhee
43 - Brandy
44 - Chris Brown
45 - Amerie
46 - Ayumi Hamazaki
47 - Ricky Martнn
48 - Simple Plan
49 - Alicia Keys
50 - Joss Stone
51 - Duffy
52 - Green Day
53 - Maite Perroni
54 - Fergie
55 - Koda Kumi
56 - Nelly
57 - Kylie Minogue
58 - Linkin Park
59 - Hayley Willians
60 - Lily Allen
61 - Chieco Kawabe
62 - Rascal Flatts
63 - Cyndi Lauper
64 - Ashlee Simpson
65 - Usher
66 - Selena Gomez
67 - Emma Lahana
68 - Jay.Z
69 - Natasha Bendingfield
70 - Demi Lovato
71 - Michelle Willians
72 - Ashanti
73 - Christina Millian
74 - Hayden Panettiere
75 - Keri Hilson
76 - Kat DeLuna
77 - T.A.T.U
78 - Colbie Caillat
79 - Lindsay Lohan
80 - Vanessa Hudgens
81 - Gorillaz
82 - Vanessa Carlton
83 - Namie Amuro
84 - Kazufumi Miyasawa
85 - Utada Hikaru
86 - Enka
87 - Enya
88 - Laura Pausini
89 - Mika Nakashima
90 - Noriko Sakai
91 - Tila Tequila
92 - Glуria Estefan
93 - Cher
94 - Jessica Sutta
95 - Mandy Moore
96 - Yuna Ito
97 - Avril Lavigne
98 - Pink
99 - Dulce Marнa
100 - Miley Cyrus