Under 3 oz. and for me the delica is hard to beat as an edc blade. I have better more expensive blades but I can't find a better blade to pocket edc. It is 2.5 oz with a blade just under 3 inches so it does not attract to much attention
Really depends. If I got a heavy on-person load that day, then I'll carry something light. If I'm carrying next to nothing, I'd chose a heavier knife. I usually have 3-4 knives out in my rotation, and switch them depending on the day and what other gear I'll need to be carrying. The weight for me (folding knives) is maxed out at 5.5-6 ounces. I don't like a real heavy folder, and 5oz is really stretching it.
The photo below is an old photo but it will give an example of the type of knives that I carry. I think 3-4 ounces is about what I carry, but I don't mind a bit heavier. I clip my knives to my jeans pocket and truthfully I can't tell if I even have the knife or not. When I pull the knife out to use it I can feel the weight and it makes a tiny bit of difference to me, but usually weight is not a factor. I was buying bigger and bigger knives and when I finally got to a ZT 0200 I thought I had gotten a knife bigger than what I liked so I ultimately sold that one.
I've recently started EDCing a Benchmade 757 that weighs in at 6.5 oz. For how big that knife is, I really don't notice it in my pocket. Sometimes I don't mind the weight as added reassurance that the knife is there. If I'm wearing shorts, then I'll go for something light like a mini-grip. Like others have said, it depends on what I'm doing and wearing. Sporting a 4" blade in the office doesn't go over too well so at work I EDC something smaller and therefore lighter.