I work in IS (Information SYstems) for a major automotive OEM. The environment I work in is a professional office where people wear "dress casual" (dockers or dress pants, polo or button-down shirts and sometimes ties and suits). I usually am in khaki Dockers and button-down or polo shirts. My choice of office EDC is a folder with a blade ~3". I always carry it clipped in my right-front pocket. My shirts are usually tucked in so the clipped knife is clearly visible. I have carried this way for 7 years now at this same company and never had anyone "complain". I interact often with all departments and with many different people form engineers, managers, VP's, directors, secretaries to facilities/security.
It all depends on how you present yourself in a white collar environment. I think if you are dressed professionally, act professionally and don't give people the opportunity to think you are some crazed knife freak, then you carrying a knife will not be interpreted as threatening. I don't "whip out" my knife at every opportunity to use it but when I do need to use it, it is brought out in a non-threatening or "non-showy" way. I cut what needs to be cut and put it right away when done.
As far as what knives I EDC, lately, I carry either a Kershaw Skyline, Kershaw Blur CB, Kershaw Leek or Buck Vantage Pro. I have on occasion gone as large as a Spyderco Endura 4 G-10 and Benchmade 710 D2 but I am not comfortable carrying folders that large so I usually don't. I only use it descretly and usually in the data center or our department, both of which are away from the general population. The data center is especially out of the way since it is in a locked secured area and access is limited. The smaller the blade, the better in an office environment. Our actual company policy does not state a specific length, but talking to HR and my managers, 3" is the most they would like to see in the office. Most SAK's will not even raise and eyebrow here and many do carry those including my manager. Oh, and I think if you carry other EDC items like a flashlight (Quark Mini123 for me), a Fisher pen & Moleskine pad and/or a multitool (I often carry a SwissTool Spirit), the knife is seen more as a tool and not a weapon.
