Oricon has posted an article about the top 10 selling anime theme songs of 2005.

Thirty-seven Anime Theme Songs broke into Oricon's top 10 charts this year, compared to 24 in 2004 and only 8 back in 2000.

This year's top 10 anime theme songs were:

1) "*~Asterisk" from Bleach (TV), by Orange Range - 628,329 copies sold
2) "Gekkouka" from Black Jack, by Janne Da Arc - 321,977 copies sold
3) "Sukiyanen, Osaka/Oh! Enka/Mugendai" from Nintama Rantarou, by Kan Johnny 8 - 238,826 copies sold
4) "Link" from Fullmetal Alchemist: The Conqueror of Shambala, by L'Arc-en-Ciel - 235,751 copies sold
5) "Pride" from Gundam Seed Destiny, by High And Mighty Color - 223,208 copies sold
6) "vestige" from Gundam Seed Destiny, by T.M. Revolution - 176,028 copies sold
7) "Metamorphoze" from Mobile Suit Zeta Gundam: A New Translation -Heirs to the Stars-, by Gackt - 156,709 copies sold
8) "Kimi wa Boku ni Niteiru" from Gundam Seed Destiny, by See-Saw - 156,172 copies sold
9) "Kuroge Wagyuu Joushio Tanyaki Roppyaku Hachijuu En" from Black Jack, by Ai Ohtsuka - 149,134 copies sold
10) "Wings Of Words" from Gundam Seed Destiny, by Chemistry - 140,969 copies sold

Thank You: Anime News Network for this information and the fine translation of it.