I like all kinds, but Jack Russel terriers can be a bit much. I grew up with one and my sister has one, and they're cute and smart as can be, but I could never have one; they are too hyper. I love the ones that have been in my life, but they require more attention than I could give it--of course, I'm more of a cat person, myself.
Cocker Spaniels, it seems, are never terribly bright. They're sweet and cuddly, but I've never met one that seemed all that smart. I don't know, maybe I've just met some people with poorly trained cocker spaniels.
I really love dogs from colder climates; Huskies, Malamutes, Samoyeds, and all kinds of sheep herding dogs. They are just so pretty and seem to exemplify "man's best friend" to me. Whether they're herding, sledding, hunting, they are just such cool companions. If I ever have dogs, I'd love to have a couple of Huskies.
I also have a warm place in my heart for Bulldogs. How can you not love them? They're so ugly, they're adorable.