All just my personal opinion
The three clarinet concertos (E♭ major, op.1; F minor, op.5; B♭ major, op.11) by Bernhard Henrik Crusell (1775 – 1838), in two recordings: Emma Johnson (RPO and ECO, various conductors, 1986 – 1991), and the 2008 recording with Martin Fröst (Okko Kamu, Gothenburg Symphony Orchestra)
Bruckner: Mass No.2 in E minor — comparing 6 versions of Anton Bruckner’s Mass No.2 in E minor. Artists: Eugen Jochum/Chor des Bayerischen Rundfunks (1971) — Daniel Barenboim/John Alldis Choir (1974) — Philippe Herreweghe/La Chapelle Royale & Collegium Vocale (1989) — Simon Halsey/CBSO Chorus (1990) — Helmuth Rilling/Gächinger Kantorei (1996) — Stephen Layton/Polyphony (2007)
Comparing recordings with the following artists: Géza Anda, Camerata Academica (1962) / Vladimir Ashkenazy, Philharmonia Orchestra (1978) / Daniel Barenboim, English Chamber Orchestra (1971), Kristian Bezuidenhout, Petra Müllejans, Freiburger Barockorchester (2012)
Mozart: Piano Concerto No.17 in G major, K.453 — comparing recordings with the following artists: Géza Anda (1962), Vladimir Ashkenazy (1977), Daniel Barenboim (1968), Kristian Bezuidenhout/Petra Müllejans (2012), Arthur Rubinstein/Alfred Wallenstein (1962), Andreas Staier (1995)
Bach, St.John Passion BWV 245, with the following artists: Harnoncourt / Equiluz (1965), Jochum / Haefliger (1967), Rotzsch / Schreier (1976), Koopman / de Mey (1993), Suzuki / Türk (1998), Gardiner / Padmore (2003), Layton / Bostridge (2012)
Bach: Cantata BWV 140, “Wachet auf, ruft uns die Stimme” — Comparing 5 recordings: Leppard/English Chamber Orchestra, London Voices (1981), Harnoncourt/Concentus musicus (1984, partial), Gardiner/Monteverdi Choir/English Baroque Soloists (1992), Koopman/Amsterdam Baroque Orchestra & Choir (2006), Lutz/J.S.Bach-Stiftung St.Gallen (2008, DVD)