Everybody has an idea of the best dog for a truck is. Unfortunately, you are the only one who can determine what the best dog for YOU is. A few pointers on what is important on picking a dog:
-Do NOT get one from a puppy farm. A puppy farm is not the same as being raised on a farm. Puppy farms are breeders who breed to make a buck, plain and simple. They tend to be hyper (from being locked in cages), not healthy, and you would be promoting the industry to pump out more of these pets. If they aren't sold, they tend to be put down.
-If you get one from the shelter, spend time with it, to understand its temperment... skittish, hyper, friendly, cowering, etc. Mutts can be some of the best dogs, and they need good homes too.
-A dog that's a year or two old has its personality already, whereas a puppy could have an undesirable trait hidden until it gets older. Our dog, Cooper, was a hyper, energetic puppy; and now is an energetic 1 yr old. We've recently found out he's a much more calm dog with an Alpha (in this case, a female doberman mix) dominating him. He's always wanted to be dominated, but not necessarily by humans. His herding instincts (he's a mini Aussie Shepherd) are now restricted to rarely herding the cats. He doesn't mess with the kids so much anymore. IOW, he needed another dog in the house.
I took the liberty on doing a breed selector quiz based on what you mentioned you wanted. You should probably do the same just to get an idea. But keep in mind that this is not foolproof. You could get an entirely wrong breed for the truck (a pug is a bad breed for severe climate changes, but came up as a possible match), or for you. Also, you aren't going to get EVERYTHING you want in a dog. You may have to put up with grooming three times a week, or loud barking at strangers, or more than average training time, or a dog that likes to exercise more than you do.
Here's a couple you may want to look into further...
Cavalier King Charles Spaniel
Welcome to PuppyFinder.com - The Most Comprehensive Online Resource for Finding and Raising a Puppy!
Miniature Schnauzer
Welcome to PuppyFinder.com - The Most Comprehensive Online Resource for Finding and Raising a Puppy!
Sealyham Terrier
Welcome to PuppyFinder.com - The Most Comprehensive Online Resource for Finding and Raising a Puppy!
Here's the link for the breed selector, so you can fine tune your own wants and needs:
Welcome to PuppyFinder.com - The Most Comprehensive Online Resource for Finding and Raising a Puppy!
Let me know what you come up with.