Since you are interested in Michala Petri plays Concertos & Sonatas, here is a list of other items that you may find interesting.
BEETHOVEN / BRAHMS / MOZART
Leon Fleisher Plays Beethoven & Brahms [5 CD set]
Leon Fleisher (piano) / The Cleveland Orchestra, George Szell
[ Sony Classical Masters / 5 CD Box Set - released 20/May/2012 ]
"Fleisher has the ability to take the slow movement slowly, and the molto adagio cadenza near its end is for once as slow as the composer could wish, and very impressive. The finale has plenty of fire" (Gramophone on the Brahms Concerto No 1)
Anner Bylsma plays Boccherini [5 CD set]
Anner Bylsma (cello) with various accompaniments
[ Sony Classical Masters / 5 CD Box Set - released 10/Apr/2012 ]
"Anner Bylsma is a tremendous enthusiast, whose high spirits and nervous energy never fail to manifest themselves in his performances." (Gramophone)
HILDEGARD von BINGEN
Canticles Of Ecstasy / Voice Of The Blood / Ordo Virtutum / Saints / etc
Sequentia, Barbara Thornton & Benjamin Bagby (directors)
[ Sony Classical Masters / 8 CD Box Set - released 1/Sep/2011 ]
"In this first-rate traversal of her music--the most popular of several volumes released by the early-music ensemble Sequentia--we hear music that resulted from Hildegard's legendary visions, which often included song texts that she subsequently...
W. A. MOZART
Bruno Walter conducts Mozart [6 CD set]
Zino Francescatti (violin) Irmgard Seefried (soprano), Jennie Tourel (alto), Léopold Simoneau (tenor) & William Warfield (bass) / Columbia Symphony
[ Sony Classical Masters / 6 CD Box Set - released 1/Sep/2011 ]
Born in Berlin in 1876, Bruno Walter entered the Stern Conservatory at the age of eight, intending to become a concert pianist, and made his conducting debut in Cologne at 17. Following appointments in Pressburg (now Bratislava), Riga and Berlin, he...
Fritz Reiner conducts Richard Strauss (5 CDs)
Chicago Symphony Orchestra, Fritz Reiner, with Antonio Janiqro (cello) Bryon janis (piano) Inqu Borkh (soprano)
[ Sony Classical Masters / 5 CD Box Set - released 20/May/2011 ]
"These were the first stereo sessions the RCA engineers arranged with Fritz Reiner. The RCA recording team 'got it right' from the very beginning. Reiner achieves an admirable balance and whatever he does is convincing." Rosette (Penguin Stereo Guide)