@vedric You are very clear about the importance of sound quality. A great way to introduce yourself to the musical offerings of a variety of composers is going to Reference Recordings website or searching them on Amazon. Their redbook CDs and SACDs are legendary for their sound quality. I was just listening to "Ports of Call" a disc of a variety of well known compositions from the Romantic Period. Solid performances in natural, open sound.
Suggested Reference Recordings:
*Reveries - Lush, open sound of some of the most relaxing symphonic music available.
*Baroque Favorites - This is a particularly great deal as it includes two discs that originally were released as two separate offerings. I am not a huge fan of Baroque Period pieces but I own and enjoy this.
*Bolero! Very eclectic collection of interesting Impressionistic offerings. Great sound quality as usual with the possible exception of the first cut which was, to my ears, recorded a bit too loudly relative to the rest of the disc.
*Mephisto & Co. This is classic Reference Recordings. Well known repertoire from a variety of composers with the usual great sound. Very dynamic!
*Exotic Dances from the Opera - No vocals, but this is perhaps the best known RR offering among audiophiles. This is so beloved that it has recently been remastered to hybrid SACD. I have the CD. I can only imagine what the SACD sounds like.
*Fiesta! This contains offerings from Spanish composers with an absolutely killer bass drum!
There are other great discs to be had but the above mentioned offerings would be a good place to start. You can listen to 30 second samples to see if the individual discs float your boat. Hope this is helpful!