His portrayal of the self aware hologram Vic on DS9 was always a highlight for me. In the midst of an ongoing war epic, they’d sprinkle in moments for Fontaine to cheer/distract the crew and audience. His beautiful voice helped Nog through the loss of his leg and the PTSD incurred from battle. He got Odo to remove the proverbial stick from his ass. Plus, he helped to orchestrate a ridiculous heist on the holodeck in order to save his program. He will be missed.
James Darren was also in T. J. Hooker, which starred William Shatner, giving him a double-Star Trek connection.