A SAK is my only true EDC- on my keyring. Either a blue alox Classic on the weekends or a Wenger Air Traveler on schooldays. I also have a Swisscard, sans knife, in my back pocket, by the bandana. I have it there mainly for the 4-way screwdriver and the light, although the pen comes in handy too.
The Explorer lives on my desk, and is used for chroes around the house. The Recruit and Wenger Canyon and Electrician Plus all find their way into the carry rotation sometimes. The Recruit was my first, has a certain nostalgia, so I mainly carry the Canyon over it. The Canyon was the knife that I had when I went to Switzerland, and it served me well, and continues to do so. It's a well-designed piece of hardware.
The main carry pieces these days are the Victorinox Helmsman and the Wenger 55. They're big, and not red, but they handle heavy duty cutting well and carry pretty well on the belt.
My only other SAK is a Pocket Pal, which is actually an Eisenhower style penknife. Sharp, slim little bugger, that goes with me places when anything bigger would be innapropriate.
I also have a Leatherman Kick that I carry from time to time. Not technically an SAK, but still dead useful.