i say:

Peter hammill - Over

Naming the person you broke up with by name and accussing her of every nasty thing ever is pretty bad form.

Marvin Gaye - Here, My Dear

After his divorce, Marvin made a settlement where he had to give half of the royalties from his new project to his ex-wife. So he made that project a double album about their divorce and how much of a bitch she was. Classic.