Well, I got slightly more of yours than you did of mine. But only slightly. :-)

6. - David Bowie, Life On Mars
8 - Aimee Mann, Pavlov's Bell (from 'Lost In Space')
11. Kate Bush, Wuthering Heights (from 'The Kick Inside')
20 - (I think) 'I Fall Asleep' by Blondie?

I'm going to guess that 1-5, 7, 9-10 and 12-20 are all by Tom McRae. :-)