I think personally that Patrick McGoohan is a really cool and brilliant actor, one of the best of his generation. He is great in everything he's in, from "The Prisoner" to "Escape from Alcatraz", from "A Time to Kill" to "The Simpsons". It's a shame that he turned down the chance to play James Bond (it would've been great if the first Bond was an Irish guy!) and Gandalf in the "Lord of the Rings" trilogy (ditto).
I mostly know him from "The Prisoner", which I saw for the first time this week. I watched all 17 episodes over four days. He was truly a visionary when he developed the series. I just wish he'd come forward and explain what the hell the last episode means! I doubt the answers exist anywhere except his mind. My least favourite episode was "Do Not Forsake Me, Oh My Darling" for the very reason that he was only in ONE scene, at least in original footage. I missed his dry British (his character was British, but he's Irish) wit throughout that episode and thought Nigel Stock was a pretty poor substitute.
In terms of coolness and humour, he really is the Irish equivalent of Richard Dean Anderson.