The entire Heaven and Hell and Mob Rules albums are flawless. I own the Elf material but only listened to it once so I'm not very familiar with it. The Elf stuff is what made Ritchie Blackmore want to make music with him.
He eventually left Rainbow because he didn't want to go in the 'pop' direction. The song "Rainbow In The Dark" is his opinion of Ritchie Blackmore.
Graham Bonnet replaced Ronnie and sand the radio hits "All Night Long" and "Since You Been Gone". Graham was fired after a drunken performance and replaced with Joe Lynn Turner who did too many radio hits to list. You probably know them, but "Stone Cold" and "Street of Dreams" are among my favorites.
Graham Bonnet went on to join Yngwie Malmsteen in Alcatrazz. Ronnie also recorded a song with Yngwie. They did Aerosmith's "Dream On", which is worth a listen, if you haven't heard it.
OK, I'd better stop because it's time.
Now I'm going to blast some SERIOUS metal. :-)