TOD: The recent revival of "Gypsy" was a revelation to me. I had seen the show many times in the past, but never one as powerful as this, and part of that was because of Patti LuPone. She was amazing in how she won you over and then chewed you up for getting too close. She was the most charming and evil monster imaginable. Brilliant.
Other memorables on the musicals list must include Anita Morris in "Nine," Bernadette Peters in "Sunday in the Park with George," John McMartin and Barbara Barrie in "A Little Night Music" (a lot of Sondheim on that list), and Carol Channing in "Hello, Dolly!"
As for non-musicals, two shows stick out in my mind. I saw George Furth's "Precious Sons" in an early preview, and both Judith Ivey and Ed Harris blew me away, especially at the end where she willfully destroys her husband and he willingly allows it to happen. I thought about that scene for weeks after that it was so chilling. I understand it was watered down by opening, but what I saw was as shocking and painful as the ending of "Suddenly Last Summer."
On a lighter note, I also loved the entire cast of the Rosemary Harris revival of "Hay Fever," in which the incomparable Charles Kimbrough gave a deftly funny performance that stole the show from a cast of scene-stealers. Deborah Rush was also hysterical in that.