All just my personal opinion
Schumann, Symphony No.1 in B♭ major, op.38 — comparing 5 recordings: Bernstein / Vienna Philharmonics (1984); Harnoncourt / Chamber Orchestra of Europe (1996); Gardiner / Orchestre Révolutionnaire et Romantique (1997); Zinman / Tonhalle Orchestra Zurich (2004); Dausgaard / Swedish Chamber Orchestra Örebro (2007)
Beethoven: Violin Concerto in D major, op.61 — comparing recordings with the following artists: Batiashvili (2007), Busch/Busch (1942), Faust/Abbado (2010), Francescatti/Walter (1961), Grumiaux/Galliera (1966), Heifetz/Munch (1955), Huberman/Szell (1934), Jansen/Järvi (2009), Kennedy (2007), Kopatchinskaja/Herreweghe (2009), Kreisler/Blech (1926), Kremer/Harnoncourt (1992), Menuhin/Furtwängler (1947), Milstein/Szell (1964), Mullova/Gardiner (2002), Oistrakh/Gauk (1952), Oistrakh/Cluytens (1959), Stern/Bernstein (1959), Szeryng/Schmidt-Isserstedt (1965), Suk/Konwitschny (1962), Tetzlaff/Zinman (2005), Zehetmair/Brüggen (1997)
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: The Motets — comparing recordings with the following artists: Bernius (2012), Christophers (1989), Gardiner (1980), Gardiner (2011), Harnoncourt (1980), Herreweghe (1985), Junghänel (1995), Katschner (2012)
Mendelssohn violin concerto op.64: Comparing recordings with the following artists: Kreisler/Blech (1926), Mullova/Gardiner (2002), Tetzlaff/Järvi (2008)
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)