This is an unusual question- I don't have any "worst blades" in my collection, depending on how you define "worst" I guess. My collection would range from "good" to "real good" or they wouldn't be in my collection.
So I can say that my best blades, judged by price, would be ZT 0561, BM 581, and green Paramilitary 2. The knife the I like most would be my BM 913. So I can't say that I have any "worst" knives, but at this one the ones that I like a tiny bit less than the others would be Kershaw Blur and Spyderco Tenacious. Actually I still have an old BM mini-grip too.
Right now I have 15 different knives in my EDC rotation (holy crap, how did I get that many!), and I like all of them for one reason or another. They would not be in my EDC rotation if I didn't like them. (Looks like I'm going to have to sell a few.)