I keep a sheath knife in my bag, as large a one as I think I might need for the day.
I don't carry a large lockblade. I usually have on my belt a Victorinox Soldier (an old-school aluminum sided one, like a Scout or Camp knife, not the bizarro new one), and in my left front pocket, a Victorinox Executive (which is really all the knife I usually need in a day, but I digress). In my right rear pocket, I usually have a Case Slimline Trapper (single blade). If I'm at work, that Trapper might be in my front pocket, or another knife might be there, like a Queen large teardrop, or another Case like the Medium Texas Jack, or any of a number of others. If I'm not at work, my right front pocket is usually occupied by S&W.