I just found this link that tells you how to get back the old color icons (instead of the grey ones) in iTunes. It looks like it's only for the mac version. I just tried it out, and it actually worked, which surprised me. I hope that you guys will find this useful for those who don't like the grey icons in iTunes
http://forums.applenova.com/showthread.php?p=735792
http://forums.applenova.com/showthread.php?p=735792