I re-read the original post carefully and I see that he's not asking for recommendations since he already has knives that he carries in his dress pants, but was just wondering what the rest of us carry.
So to clarify my earlier post. I only wear jeans maybe once a week at work (Fridays). I work in an office and my slacks could fall under the "dress slacks" category. No cargo pockets, no carpenters pants, no watch pocket. 4 pockets. So I don't have a special "dress pants" carry because that's my all of the time carry.
So I carry whatever I want to carry that day. I rarely go smaller than 3 1/4" closed length, and rarely go over 4 1/4" closed length. Within that range I carry stockmans, jacks, trappers, muskrat. Made by Case or Buck.
If I weren't into pocket knives as a hobby and just wanted to carry a cutting tool for the pure utility of it, I'd carry a Victorniox Alox Cadet and never look at another knife. In fact I find the Cadet handy enough to where I've started carrying one of them in addition to whatever else I'm carrying.