@tsarstepan,
As much as I have loved this show, and can endlessly watch the reruns, I find the current cast to be be very lackluster, perhaps because the characters they play seem to lack definite personalities.
Over the years I have particularly enjoyed:
Steven Hill
Jerry Ohrbach
Michael Moriarty
Jesse Martin
S. Epatha Merkerson
Sam Waterston
Jill Hennesy
Chris Noth
And these two grew on me as time went on...
Angie Harmon
Dennis Farina
And, in his short stint, I really liked
Michael Imperioli
One of the biggest disappointments, for me, was Diane Wiest as the interim D.A., mainly because they gave this very fine actress so little to do with her role. Seeing her in
In Treatment, where she really shone, reminded me how they wasted her in L&O. But Steven Hill, like Jerry Orbach, was a tough act to follow.