Pretty much agree with what Jonathan said above, but Ritchie Blackmore's Rainbow is worth getting just for "Man On The Silver Mountain". What an awesome song. Great album cover too - I have it embroidered :oops: on the back of my old denim jacket from the first Donington in 1980!
I like Long Live more now than I did at the time - the title track, "L.A. Connection" and "Gates Of Babylon" are great songs. And "Rainbow Eyes" is a lovely ballad with one of Dio's best ever vocals (in a similar vein to Coverdale's "Soldier Of Fortune" on Stormbringer).
The Joe Lynn Turner period got increasingly dull, Difficult To Cure still has the magic though. I'd avoid Bent Out Of Shape, by that stage it seemed Blackmore was bored with his own band.
I recently bought the Live In Munich 1977 DVD, which is excellent. So different from gigs today. Blackmore, as always, seems to do whatever the hell he wants as it takes his fancy, and he's brilliant. And Dio's voice hadn't developed the hoarseness he has nowadays.
There are also several live Rainbow albums which have been released in the last few years, I haven't got any of them so don't know which are the good ones.