I agree the 4th Symphony is a good place to start with Bruckner.
Then the 7th as well. For the 7th three good choices (all on Deutche Grammophon) are;
Vienna Phil/Von Karajan, DG 429 226-2
Vienna Phil/Giulini, DG 419 627-2
Berlin/Jochum; DG 429 079-2
For the 8th, I also agree with the 2CD set of the 1989 Von Karajan recording with the Vienna Phil.
Then the 7th as well. For the 7th three good choices (all on Deutche Grammophon) are;
Vienna Phil/Von Karajan, DG 429 226-2
Vienna Phil/Giulini, DG 419 627-2
Berlin/Jochum; DG 429 079-2
For the 8th, I also agree with the 2CD set of the 1989 Von Karajan recording with the Vienna Phil.