Rocky III (album wise) was basically a greatest hits compilation of I and II, but they're my favorite renditions of each track, which is why it's the only Rocky score I have so far (missed out on Intrada's IV). And yes, I'm that one weirdo who even likes the Frank Stallone track... a lot.
ROCKY III also marks the debut of "Mickey," arguably the most beautiful piece Conti has written. I know a lot of people who don't care about film music who mentioned being moved by it.