Oh, and about the look and feel of iTunes 5: Aside from the stylistic implications which will differ with taste, I'd like to add that I don't like that the usability of iTunes 5 seems to have suffered.
The lack of spacing between the source list and the edge of the window (there used to be a nice frame there) makes it too easy to accidentally click outside of the app window when selecting a source. Also this is poor design visually since the contents of iTunes is not clearly seprated from windows appearing behind it.
Another thing I have noticed is that when I'm playing an album from my library and I browse to another location in the library iTunes plays a track from the currely viewed area and doesn't continue to play the album like it did in version 4. I'm a bit confused about what is happening exactly here so if someone can clarify how this is supposed to work under 5, that would be very helpful. All I know is it's behaving differently than 4.