What type of collar do you prefer?

 Nekkid at home and leather buckle for walks.

tiffy

 Nekkid at home and leather buckle for walks.

Ditto.

 either a 2 inch leather buckle or a 2 inch cloth martingale.

 Although for the sake of fashion...sometimes I use a sense-ation harness on walks so she can wear one of her 1 inch leather buckles.

 For daily use we have leather martingales with chain loops. For bike rides and some other occasions the dogs will wear harnesses. Hiili trains with a slip collar, because it's compulsory for her to wear one during obedience in working trials. She gets very excited, when ever I take a slip collar out. On certain occasions one or both dogs may wear flat buckle collars. And naturally the dogs don't have any collars on at home or while running free. During the winter they'll have reflector bands with velcro around their necks while we go to the forest.

I might be a slight collar nut, so we have a few extras just for fun, that the dogs will wear on "special" occasions, like so:

Generally my dogs don't wear any collars at home, but if we're having company over, I'll put their collars on. For walks the Dobermans will either wear martingales or they'll wear a flat collar with ID and a prong collar (depending on where we're going/what we're doing). Dance has an assortment of martingales and flat collars, and it doesn't matter what she wears. Usually though if I'm attaching a leash to her collar, I put a martingale on her. If I'm going to Agility classes or walking her in a slip lead, she wears a flat collar. And while I prefer the look of leather, all of my dogs have an assortment of nylon, hemp and leather collars (and Dance also has one coated waterproof collar).

 Dahlia doesn't wear a collar in the house so I prefer something that's quick and easy to put on.  She wears a snap collar.  She doesn't pull hard on the leash so I'm not worried about her breaking it.