I like schnauzers, would probably like Shelties more other than how sensitive a lot of them are, but I have had dogs that are sensitive and am fine with it, just not a trait I would be hoping for. I like jack Russells. I think I will love koolies from what I have seen and heard of them.
I wouldn't own a lot of small dogs, because I don't like dogs that are too fragile (also part of the reason I like terriers), I also am getting tired of having to be so careful with them (looking for wildlife like coyotes, eagles, owls, etc), them getting under my feet and me not seeing them/tripping over them, etc. so I am ready to move to medium dogs (~30-40lbs) from now on.
I like the terrier personality, but also like many herders.