"Thirds" is under-appreciated, in my view. James Gang tried to find a new identity after "Thirds", when Joe Walsh left. They added Dominic Troiano on guitar and Roy Kenner on vocals for two albums that were merely OK, and not essential listening. But then they re-emerged with Tommy Bolin adding searing guitar and some pretty good tunes. Two albums, "Bang" and "Miami" resulted. "Bang" is the better of the two, but "Miami" is good, too.
(Dominic Troiano also stepped into the Guess Who after Randy Bachman's departure, incidentally, but GW's post-Randy albums were not their best,either).
If you find you enjoy Tommy Bolin, you might search out Billy Cobham's "Spectrum", an interesting jazz-rock-fusion collaboration.
And, if you fancy Joe Walsh, don't miss his first solo album, "Barnstorm".