I am the now proud owner of an Itouch given to me by my kids and wife (to be more precise, the Itouch came from my wife and the protective cover from my kids ..). It is now constantly with me and I have transferred the music I have from various sources. The first one which I used is Itunes.
My experience of Itunes for classical music is just terrible. The classical home page is messy. Itunes does not remember that I go there mostly whereas cookie technologie is simple to deploy and classification is average at best. On top, as I have changed countries and have had to modify my account, there is some music I can access from my PC but not my Itouch.
For my day work (I am currently in Orlando for my day job at the Lotusphere Tradeshow), I have met Julian Woodward who has developed the Hyperion download site. Have a look at it, it is a site designed for classical music fans by an genuine IT proficient classical music lover. For info, the Schubert series weights 48 Go and has been downloaded several times.