I'm thoroughly enjoying Amarok and Last.fm together and I'm looking forward to 2.0 coming out so that Amarok doesn't keep freezing and hanging.

I don't know if this is being addressed in 2.0, but:

Amarok has a default list of Global tags for Last.fm that you can connect to, these include "Ambient", "Chill Out", "Rap", "Rock" and so on. The thing is, of course, that there is a large amount of musical sub genres that also have Last.fm tags, like "Japanese Hardcore", "Coldwave", "Power Violence", "Psychobilly", "Sludge Metal" and so on.

Amarok does not let me add these sub genres to the Global Tag list. It have been able to create a "Global Tags 2" folder, but I am unable to change or add anything to the default list. Can this be changed?

The UI for the last.fm service isn't done in Amarok 2, but I'd hope to make it so you can have whatever stations you want for easy access.

Not sure how it's implemented in Amarok 1.