I think all of his styles were good except maybe on Quiet Life/Second That Emotion promo videos. That blond nest hair was horrendous! Also the complete look in combination with bright red lipstick was just too feminine for me.
Initial glam-look was great, suited his voice very well and I take 'Quiet' phase as a transitional to more elegant and stylish 'Tin Drum' era.
Later he got some 'hippy' periods during the late '80s I think which I didn't like, but everything else was just fine.
IMO he looked the best during '90s with his short dark hair which emphasized his wide smile and still handsome face (I think Ingrid had to do something with this

)
His current look I find very distinguished and compatible with his age.
@Tracy if u wanna see David looks very Beckham alike, just check out this one....
http://www.youtube.com/watch?v=7K9JTj7oRXQ