Earlier this year my anime CD collection really took off. I've been buying what rightstuf had along with new and used CDs from sellers here in the U.S. and Japan. The most expensive new CD was the original Gunbuster box set ($110) which is my pride and joy. It includes the OP and ED by Noriko Sakai which are rare because she was blacklisted for drug charges--I don't think that's fair at all considering the lifestyles of American musicians.
The most expensive used CD was the OST to Gunfrontier ($60). My most expensive itunes purchase was the Sakura Taisen Song Box ($70) not bad considering it's 8 CDs. I buy from itunes Japan as well. J-box sells Japanese itunes cards if you're interested
I scanned all my CD covers, copied all my itunes artwork and uploaded them online. I've listed my favorite tracks and artists for each as well. The pages are laid out like photobucket. I've seen most of what I own except for a few. http://animuze.com/gallery/index.php/My-Anime-Music-Playlist
(124 albums, 963 songs, 2.2 days, 6.35GB)