^ Disco Heaven is not just on the UK release, it's all over Europe, I have it on my Dutch CD as well.
Anyways, I've never even heard Again, Again and Retro, Dance, Freak before! Time to youtube them. And 'cause y'all are lazy, the links:
Again, Again
http://www.youtube.com/watch?v=Jwtbp92-is8
I don't really like it.. but it's not like her other songs.
Retro, Dance, Freak
http://www.youtube.com/watch?v=f-RIr2tE63s
Don't like it either :S Guess this is why they're bonus tracks though. haha.
Guess I'll base my decision on the look of the covers / packaging.