I haven't had a dog villager in New Leaf yet but I had Butch in WW and I loved him! He's adorable!
But I also love Cookie because she lived in my GC game when we also had a IRL dog named Cookie
Goldie.. She's the only dog villager I could actually tolerate besides possibly Shep.. I just HATE practically all dogs.. Mainly 'cos I tend to form attachments to villagers with how they were in WW, as I used to play that tons, and cycle through lots of villagers.. And all the dogs are awful, particularly Bones and Portia