From an interview on totalscifionline.com http://totalscifionline.com/interviews/5107-david-hewlett-the-real-mckay
David Hewlett talks a bit about the series:
"Can you talk a bit about your character’s relationship with Colonel John Sheppard, played by Joe Flanigan?
At first it was basically oil and water. McKay said one thing and Sheppard said another – it’s just that my character took a lot longer to say it. Depending, then, on the episode, McKay was either proven right or wrong.
Eventually, however, they found this rhythm with the two of them. I don’t know if it was Joe who originally came up with the idea, but he was the one who first mentioned it to me. Joe said, “We’ve got to be more like Bob Hope and Bing Crosby in the classic movie comedies.” Here are these two guys who are total opposites – one is this suave leading man and the other one thinks he is, do you know what I mean?
Once we started doing that, it was great. I fondly remember those walks and talks on our strangely always forested planets, with McKay and Sheppard whining about something other than what was going on in the episode. "
"What did you think of the Atlantis series finale Enemy at the Gate?
I’m not a big fan of Enemy at the Gate. As far as trying to wrap up five years of a show, it just didn’t work. It felt like just another episode, but it really wasn’t. It was an opportunity to do something memorable, to give people something to talk about, but it was an opportunity missed.
I think [the penultimate season five episode] Vegas should have been Atlantis’ swan song. It was so cool, off-the-wall and different for us. I just loved it. The first time I read the script I thought, “This isn’t even an Atlantis episode,” and then I was like, “Well, good!” Can you imagine, people would have been freaking out – what the hell, Sheppard’s dead, and McKay is married? If I was running the show, that’s what I’d have done. "