I think that many people who start carrying knives regularly tend to get knives that are big, then if they continue to carry knives regularly, they settle on something smaller.
I would suggest a good-quality, medium-sized knife to begin with, then if your carry and use experience tells you that you need a "full-sized" knife, get something bigger. A 550 or 551 Griptilian is relatively inexpensive, but certainly high-quality, and all the knife most people need. After lots of experimentation, I've pretty much settled on the BM 940 as my EDC.
As far as the 806 goes, I'm sure lots of people carry one every day. It's not much more conspicuous than any other knife if it's clipped to your pocket. It's invisible in the front pocket of jeans or khakis. If you wear dress pants, it's probably not the best choice because it is a very solid and weighty knife and you'll feel it a lot more than if you were wearing more heavy-duty pants. Bottom line: If you are a casual dresser and actually need a big cutter, the 806 is a fine choice (805 is probably a better choice, but that's a matter of opinion). If you are in an urban environment or need to dress up, your cutting chores are probably going to be smaller, and I would go with something like a Griptilian.