And from "Dawn's Early Light"...The elu-u-usive cider has finally materialized!"
http://www.youtube.com/watch?v=G1b0haFT8Gk
Also from this episode, I don't have any specific quotes, but it seemed that he referred to "disciplining" his cadets with a disturbing amount of enthusiasm.
This doesn't exactly count since this thread is about lines said BY him, but I wonder how many LAST SALUTE FOR THE COMMODORE lines he wrote?
Nearly my favorite is Swanee's surprising straightforward line about his regular allowance from the Commodore -
"Well, it's called a salary, but who's kidding who?"
While not necessarily my favorites, and not really examples of McGoohan's more flamboyant style, there are a few lines in the final scene of "Identity Crisis" that strike me as amusing in a more subdued way...
"You have a warrant for everything."
"So I closed the blinds. What's so special about that?"
"You've lost me again, Mr. Columbo."
"This is an office building, I was in it at night, why should not other people be in their offices etc" (what I love about this line is the intense, unrelenting way in which he delivers it; again, not quite as eccentric as many other lines, but still a lot of fun, I think)