I don't really have a folder I carry specifically for self defense, but my most trusted folder would have to be a Sebenza. I don't currently have one though. I had a small plain that I had to sell but I'm getting a small classic wood inlay for Christmas from my wife. I've just never found a knife that I like as much and that feels so solid. They are absolutly reliable.
I havn't yet been able to handle a Strider folder, if I did and was wanting a SD knife, then the SNG would be high on my list. Looks like a great folder for hard use.
For now though, I'll be sticking with my Sebbie.