Really into the Boss at the moment, but wondering what everyone's favourite albums of his are outside of the 'classics'.

Obviously it depends heavily on personal opinion, but I'd say the generally regarded 'classics' (in quality and fame) are:
Born to Run
Darkness on the Edge of Town
The River
Born in the USA

You can probably throw Nebraska in there as well, since it's from the same classic run, even if it's nowhere near as well known (and if it wasn't in there I'm sure it would be most people's answer!)