Thanks for all the recommendations.  There is indeed Schubert on my amazon list, but it shares a disc with Mozart. 
 
[ame=http://www.amazon.com/Schubert-Piano-Quintet-Mozart-Clarinet/dp/B00000275O/ref=wl_it_dp?ie=UTF8&coliid=I251RYKYRLO4Y0&colid=22YBORMDR1443]Amazon.com: Schubert: Piano Quintet "Trout"; Mozart: Clarinet Quintet: Julius Levine, Leslie Parnas, Harold Wright, Wolfgang Amadeus Mozart, Franz Schubert, Rudolf Serkin, Philipp Naegele, Samuel Rhodes [viola], Alexander Schneider [violin], Isidore [/ame] 
 
This was from Ted Libbey's Top Ten Starter Classical CDs list, from his "NPR Guide to Building a Classical CD Collection". 
 
[ame=http://www.amazon.com/NPR-Guide-Building-Classical-Collection/dp/0761104879/ref=sr_1_3?ie=UTF8&s=books&qid=1246235905&sr=8-3]Amazon.com: The NPR Guide to Building a Classical CD Collection : The 350 Essential Works: Ted Libbey: Books[/ame] 
 
I don't know enough about classical music to critique his selections, but I have just LOVED reading this book, and haven't been disappointed in anything I've purchased as a result of his recommendations. 
 
I think you all have already figured this, but all formats are welcome: plain ole' CD, any hi-rez format, and vinyl.