Dio....what can I say, the man is amazing. So many great performances. I would recommend some of the Rainbow stuff if anyone feels he is too metal. Rainbow's On Stage is a magnificent live album.
NICE! I was going to post that the three "complete shows" from the German tour (that provided some of the material for On Stage) are must listening, even if Dio was still working on some of his stage banter.
I know it's sort of a cliché (it's the LONG SONG!) but his vocals on Stargazer are so integral to that song. "Look, look, look... on the horizon"; every time I hear that, I picture him pointing and I feel I have to turn around and look, as if the rainbow will actually be there. I was lucky enough to see him perform that live - one of his solo tours, opening for Maiden on a summer shed tour, early to mid 2000's - and it was as classic as it sounds.
Also, huge fan of the live versions of "Catch The Rainbow".
It also has to be said: while he might have been a dick to his band(s) (in my humble opinion, we've forgotten that he fell out with Blackmore, Iommi/Butler, AND Campbell) he really was the nicest guy in the world to his fans. My buddy saw him with Sabbath on the Dehumanizer tour, and it was February in Connecticut, and Dio stood outside the bus for a good 45 minutes in sub-freezing weather signing everything that was put in front of him. My bud got his ticket signed, but to this day - that was what, 20 years ago? - he still talks about how "Dio talked to him!". It wasn't just a scribble and run.