I don't have a specific breed, but I most definitely have a certain type. I love the dogs that are intelligent, energetic, independent, bold-tempered with plenty of drive, are overall healthy and are up for anything. Around 50-80 pounds is preferable. My Catahoula exemplifies these qualities, as did my Redbone before him (died in 2009 at the age of 15) and my Walker/Pit before that. I see the same qualities throughout the hounds, herding dogs, huskies, etc. That said, I have to select dogs on an individual level, since there is no one breed that's ALL the type of dog I want.
Why? I love athletic dogs, and have trained a LOT of harness dogs. My Catahoula is working on learning cani-cross, bike-joring and skijoring. His predecessor would run for miles pulling a kick sled, and hated the days that we didn't harness up and go for a run. I love a dog that will go hiking with me, and it's a plus if they enjoy carrying their own supplies in a backpack. I live in Wyoming, so there are endless opportunities to run and explore near here. All of my dogs (except the mini schnauzer who only came to us because she REALLY needed a home) have been trained to a bike, and all have been the "shelter misfits" that most other people couldn't handle. That's usually the first sign that it's the perfect dog for me ;).