The Dio years is the era I like, Heaven and hell is a their best album in my opinion, They wrote some great songs on there, very melodic unlike the overrated Ozzy stuff which for me is a bit dense !! I like lots of Ozzy solo stuff due to the great Randy Rhoads and Zak Wylde on guitar. Ozzy is a great showman but as a singer to me is god awfull, unlike Dio who has to be one of the great rock singers !!