On the whole, the 80's was my favorite decade of music. Not sure I could choose first 5 years over the last 5 years (or vice versa).
I can't stand George Michael/Wham! sorta stuff (sorry Harmony so I'll go first half I guess.
Based on the albums in the library, I would have to go with the first half of the 80's, but I will never subscribe to the old complaint that "the 80's Sucked!", I lived through them and have nothing but fond memories of the time and the music.