QUOTE (Kawasakifan @ Jun 4 2008, 12:11 PM)

Perhaps because he is a civilian now on special status with the Force but more importantly wearing a suit came from his strong sense of proper deportment that is one manifestation, dress-wise, of his need for cleanliness and order. (I could easily imagine that his uniforms were heavily starched enough to nearly stand erect without support!)
Very well said! This is something I was thinking but didn't quite know how to express. It's sort of part of the manner in which he dresses being 'him'.
And as BfloGal pointed out, there were a few times in this season where he didn't wear his 'uniform', though I'm not sure the helment actually fits into this category, he didn't want to wear it and only did so as a safety precaution. Most of the other times I can think of when he wasn't dressed like he normally is, like the jeans and tee-shirt in One the Run, the clothes in Bumps His Head, or in Cabin Fever, he was in a sense being someone else, whether because he was consiously pretending to be someone other than Adrian Monk, or because he just didn't know he was Adrian Monk. Even in Makes a Friend, he was trying to be someone else, in a sense. In Masterpiece, he was behaving like someone else, in a sense he was trying on a persona of an artists, or I suppose what he (and a lot of people) think an artist behaves, speaks and dresses like. It's similar to Randy's pimp suit in Fashion Show, he was trying out someone else.
I think it's kind of neat that the costume department makes changes to his manner of dressing to reflect what's going on inside him, to project who he thinks he is at the moment, who he wants to be, or even just alter his clothing in such a small way as having him open his top button or wear a windbreaker rather than a suit jacket in Makes a Friend. His top button in Up all night was open probably to reflect how tired he was, that he couldn't even be bothered to worry about that button.
That was one of my favorite things about Fashion Show, when Malcolm McDowell pointed out how much the way a person dresses projects their personality, and the things that they want, the person they want to be or that they want other people to think they are.