I have two commutes-- a 30 mile daily commute to job #1, and a weekly 200 mile round trip down I-95 to job #2. Both are pretty much business casual (jacket and sometimes a tie, not a full-on suit).
I usually wear overpants, textile jacket and Sidi discovery boots, with a rain suit as needed. I keep my shoes and jacket in the saddlebag, along with the next day's clothes in one of those Eagle Creek packing folders (which works out okay, wrinkle-wise).
Depending what I'm doing that day (and the weather) I either change inside at work or in the parking lot outside, and either bring the gear inside or leave everything in a duffle bag locked to the bike with one of those Pacsafe net things. Sometimes I just throw the pants in my soft bags and wear the jacket and boots in, but once you establish yourself as That Guy Who Rides His Motorcycle Every Day, there's a bit of leeway to the dress code. That's been my experience, anyway.
"I have a pawn shop typewriter now. The gov. gangsters have sprayed it with an odor that makes me sick and vomit. I type on the back door step in the fresh air." -FED