It really depends on your environment. I spend half my time at a ranch in the mountains, and the other half in my country's biggest city.
The chaps at my ranch laugh at any knife with a blade shorter than 5"-6", they've called my ESEE 3 a keychain knife. They all carry huge fixed blades openly everyday (quite normal for rural workers around here, seen almost as a basic clothing item).
On the other hand, at some of the places in the city something as tiny as an Izula will raise a few eyebrows.
I've found that "pretty" knives are seen as less threatening. I use a Charles May FireAnt, a BRK&T Mini Canadian or a Case desk knife when wearing a suit; they all have nice wood handles and leather sheaths. Nobody ever said anything about them, they are tiny and cute. One of my favourite fixed blade urban EDC knives is the Fallkniven WM1, small as it is a few people hace made silly remarks about it once or twice.
I always carry a SAK or small Leatherman no matter what else is in my pockets, not only are they handy but they are the perfect knife to use in public when you want to keep a low profile.
