Sure I am forgetting one of the all-time greats, but here goes as I travel down memory lane...
Play -- Male:
-- Jason Robards in Moon for the Misbegotten and The Country Girl
-- James Earl Jones in Fences and, especially, The Great White Hope
-- Derek Jacobi in Cyrano and Breaking the Code
-- Roger Rees in Nicholas Nickelby
-- Jim Dale in Scapino
-- Ian McKellen in Amadeus
-- Christopher Plummer in Barrymore and Inherit the Wind
-- Nathan Lane in It's Only a Play, The Man Who Came to Dinner, and The Nance
-- Michael Moriarty in Find Your Way Home
-- George C Scott in Sly Fox
-- Richard Burton in Equus...best of the three
-- Frank Langella in Dracula and Frost/Nixon
-- Henry Fonda in Clarence Darrow
-- George Rose in My Fat Friend
-- David Dukes in Bent
Play -- Female:
-- Colleen Dewhurst in Moon For the Misbegotten and Whose Afraid of Va. Woolf
-- Zoe Caldwell in The Prime of Miss Jean Brodie and Medea. (Actually did not like Master Class, so her performance seemed a little over the top)
-- Irene Worth in Sweet Bird of Youth
-- Fiona Shaw in Medea
-- Vanessa Redgrave in LDJIN, Lady From The Sea, and Orpheus Descending
-- Maggie Smith in Lettice and Lovage and Private Lives
-- Judi Dench in Amy's View
-- (Not Broadway but) Cate Blanchett in Streetcar
-- Rosemary Harris in Hay Fever and The Royal Family
-- Eva LaGallienne in The Royal Family
-- Kathleen Turner in Va. Woolf
-- Glenda Jackson in Strange Interlude
-- Cherry Jones in The Heiress and The Glass Menagerie
-- Cicely Tyson in A Trip to Bountiful
-- Jane Alexander in The Great White Hope and The Heiress
-- Swoosie Kurtz in The Fifth of July and House of Blue Leaves
Musical (Male)
-- Christopher Plummer in Cyrano
-- Nathan Lane in The Producers AND A Funny Thing
-- Phil Silvers in A Funny Thing
-- Richard Kiley in Man of La Mancha
-- Tommy Steele in Half a Sixpence
-- Hugh Jackman in Oz
-- Robert Preston in I Do! I Do!
-- Kevin Kline in Pirates of Penzance
-- Robert Lindsey in Me and My Girl
-- William Daniels in 1776
-- Jerry Orbach in Promises! Promises!
-- John Callum in Shenandoah
-- Hal Linden in The Rothschilds
-- Cleavon Little in Purlie
-- Alan Cumming in Cabaret
-- Joel Grey in Cabaret and The Grand Tour
-- Boyd Gaines in She Loves Me
-- Lin-Manuel Mirnda and Daveed Diggs for Hamilton
-- Tommy Tune in My One and Only
-- Lenny Baker in I Love My Wife
-- Colm Wilkinson in Les Mis
-- Herschel Bernardi in Fiddler on the roof
-- Antonio Banderas in Nine
-- Len Cariou in Sweeney todd
Musical (Female)
-- Barbara Harris in The Apple Tree and On a Clear Day
-- Angela Lansbury in everything: Mame, Dear World, Prettybelle, Gypsy, Sweeney Todd, ALNM. Interestingly, I was only disappointed once...in The King and I. Maybe it as lack of rehearsal time.
-- Glenn Close in Sunset Blvd.
-- Bebe Neuwirth in Chicago
-- Gwen Verdon in Chicago and Sweet Charity
-- Chita Rivera in Chicago
-- Patricia Rutledge in Darling of the Day
-- Donna Murphy in TKAI and Wonderful Town
-- Pearl Bailey in Dolly
-- Patti Lupone in Anything Goes, Evita and Sweeney Todd
-- Bernadette Peters in Gypsy
-- Sandy Duncan in Peter Pan and My one and Only
-- Katherine Hepburn in Coco
-- Mary Martin in I Do! I Do!
-- Melba Moore in Purlie
-- Alice Ripley in Next to Normal
-- Lillian Heyman in Hallelujah Baby
-- Bea Arthur and Jane Connell in Mame
-- Lotte Lenya in Cabaret
-- Alexis Smith in Follies
-- Jennifer Holiday in Dreamgirls
-- Idina Menzel in Wicked
-- Sutton Foster for Anything Goes
Special Section: Disappointments
-- Ethel Merman in Annie Get Your Gun revival. Wood.
-- Barbara Streisand in Funny Girl. Bored.
-- Zero Mostel in Fiddler. Ad-libbed too much
-- Cherry Jones in Doubt. I thought she was fine, bit Kathleen Turner should have won the Tony IMO. i just didn't see what was special.
-- Jim Dale in Barnum. Meh after Scapino
-- Michael Crawford in Phantom. It probably had more to do with the size of the role than his performance, but it just didn't seem special.