Starting with the non-vocal performances by Sinopoli, I would list these,
some of which duplicate other nominations from list members:

.  Respighi: Roman Trilogy, with NYPO on DGG (often advertised through BMG
Club)

.  Schubert Unfinished on the DG Sinopoli Collection CD (not my first
choice, but representative of his approach)

.  Bruckner 3 & 4 on DG (these showcase his productive years in Dresden)

.  Mahler 5 with the Philharmonia on DG (lyrical, edgy and
different--stimulating, if not definitive)

.  Berg/Webern/Schoenberg "Viennese School" series on Teldec (affectionate
and warm Dresden sounds)

not a sleepy run-through in the bunch...his ideas--such as the stately
Mahler Adagietto--may not be to everyone's taste, but he has taken a fresh
look at each score and clearly communicates a distinctive point of view.

Now to appreciate his gifts, Dave, you have to stretch a bit and try some of
these vocal performances:

.  Puccini: Tosca, Manon Lescaut, or Madama Butterfly on DG: sweeping drama,
big tunes and top stars in ringing sonics

.  Verdi: Rigoletto on Philips or Nabucco on DG: everything just seems to
work, and the big moments have impact

.  Schoenberg: Gurrelieder on Teldec--a good example of the big line,
building slowly at the start to a radiant finale

.  Strauss: Salome--the Teldec video is a steamy, R-rated romp that does
full justice to Strauss' colorful scoring

No doubt Sinopoli has his share of clean misses, but these recordings--plus
his Strauss collection, if you can find it--represent his art and
accomplishments while conveying a fresh-scrubbed look at each score.

Dick Claeys