I have three Linn (HD)CDs and they all sound stunning, especially the Schidlof Quartet ones
(images from amazon but get them from berkshirerecordoutlet)
I have heard perhaps a dozen CDs from Alia-Vox (Jordi Savall own label). I really love these two
but they all sound stunning and look gorgeous.
Speaking of Savall looking gorgeous, this DVD is reference quality (both technically and artistically)
I agree with lmswjm (what does that stand for?) that Naive Vivaldi Edition sounds fantastic (again both technically and artistically). Here are my favourites
Let me second radiohlite recommendation of Salonen's Stravinsky Sacre and add to it this older recording
Among the true oldies, I (surprise, surprise...) love the sound of Walter Legge mono recordings of the 50's. If you can play DVD-Audio you should get his mythical Tosca with Callas/Di Stefano/Gobbi in this format from berkshirerecordoutlet
Let me finish with a very well recorded SACD, that could have been great but unfortunately isn't...