What are the best sounding classical CDs


I am looking to start a classical collection. I am looking for some suggestions on good classical preformances that have excellent sound.
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The Mercury Living Presence Label is back on CD. As many viny-philes know, the MLP recordings are some of the best ever made. Judicious care was taken in the recording process, including using a single pair of Neumann tube powered mikes(no multi-miking garbage), recorded to 35mm high speed recording tape, and even the groove spacing on the LPs was variable based on the dynamics of the passage. The recordings capture the imaging beautifully, due to the proper miking, and the hall in which the performance took place is well captured. Perspective, space, proportion, depth, tonality, dynamics, and detail are all there - miked from the listener's point of view just slightly above the audience. These are well worth a listen if you like accurate presentation of your classical music as I do.
Thanks guys! I have ordered some of your suggestions. They should be arriving soon.
Hard to believe no one has mentioned anything from the budget ($6 or $7) Naxos label. Just a few recommendations:

Barber Violin Concerto
Boccherini Flute Quintets
Vaughan Williams Antarctica Symphony
Prokofiev Violin Concertos
Reference Recordings are always sonically second to none, especially the newest HDCD recordings. Professor Johnson must be the best recording engineer in the business. Sometimes the performances aren't up to the quality of the recording, but this is being very nit picky. If you are just starting out buying the titles that are available on Reference and are looking for excellent recordings, then look no further. If you are shopping for another version of the same work, you might prefer the performances of other conductors or orchestras. The one work that I do think is outstanding is Rimsky-Korsakov Scheherezade. This is my favorite version of this work. The Mussourgsky Pictures, however, is one of my least favorites because of the tempo at which it's performed. But sonically, no other versions begin to compare.

The newer Telarcs are excellent as well and the performances are also first rate.