Hi- As far as Bruckner's 5th goes, no offense to Aaron intended, but
Haitink is a fairly boring reading, and Welser-Moest is not any better.
Also avoid Karajan, completely boring.

In terms of shear performance, I think the most exciting on record is
the 1942 by Wilhelm Furtwangler the Berlin Philarmonic.  Of the eight
Bruckner 5th I have it is my favorite.  But, given the sound is somewhat
constricted, it might not be a good choice for an introduction to the
piece.

Jochum.  Jochum recorded this symphony several times, either his EMI or
DG releases are a great introduction to the piece.  The EMI version is
on doubles coupled with the 6th I believe for about $13.00, at least that
is what it was at Borders when I was back in the states last.  However, a
great alternative is on Tahra 247(I think), it is Jochum's last concert
with the Concertgebouw Orchestra, it was recorded about three months before
his death.  It is a monumental reading.  The audience was so thrilled with
the performance, that as an encore Jochum repeated the entire last
movement.

Hope it helps.

Gary
Niigata, Japan