I've enjoyed making fun of people who dress up their pets. Not to be a hypocrite, but I have made coats-for-warmth for my dogs. I have large dogs, though, and anything froo-froo would be insulting. My crowning glory behind the sewing machine came when I made a pink fur coat, fleece lined, with a stand-up collar, buttons and Velcro closures. I had an offer on the table for someone to buy it from me for $50. I should have taken them up on it.

If you like athletic winter outdoor activities with your dog, but your pooch doesn't have a heavy fur coat, there are many useful products available for keeping your dog warm and dry in the snow, and as a bonus, some keep their coat much cleaner.

Chilly Dogs, Inc. Of Canada
If anyone knows about perpetual cold weather, it's our fair friends to the north. This link was brought to my attention by friends in Edmonton. Their coats come in a variety of shapes and sizes for different types of dogs. They are artfully constructed, come in a variety of colors and they don't look "stoopid." For your long-eared friends, you can even get a head muff to prevent frostbite.
http://www.chillydogs.ca/index.html

K9 Topcoat : Winterize Your Dog
The Topcoat company recently expanded it's lineup to include waterproof bodysuits, rain-suits, safety vests and a wide variety of utility clothing for dogs. It is important to get the sizing correct, but once you have it right, your dog will be surprisingly comfortable. I own one of the arctic fleece coats. Other than the initial indignant glare from my dog, she is actually pretty comfortable in it. If you have a hunting dog, they have orange vision vests so you can see your dog in the field. They also manufacture vests and coats for police dogs.
http://www.k9topcoat.com

Fido Fleece
If you are a fleece and Velcro lover, these coats come in a wide variety of sizes and colors to please anyone's taste. I have a small version of the "fleece coat" for puppies. The Velcro over the back takes a little wrestling to put on the dog correctly, but it does stay in place securely. It is "male friendly" while still covering the chest and upper abdomen. They also have rain coats and four-legged coats. For the water loving canine, they also make flotation devices up to an XXL.
http://www.fidofleece.com

Ruffwear
Ruffwear is one of the leading manufacturers of outdoor gear for dogs. When you check out their Web site, make sure to see their new line of dog boots, backpacks and their travel doggie bed cleverly named the "Mt. Bachelor Pad." I have the original version of the K-9 Overcoat, they are now selling an upgraded pattern. It looks like they made some much-needed improvements. The coat I have is like trying to fit puzzle pieces on the dog, too much Velcro and too many clips - everywhere. The dog did find the coat to be quite comfortable and as a bonus it had pockets and even a place to stow a water bottle. Ruffwear also sells floatation devices and toys.
http://www.ruffwear.com

Ebay
If homespun and unique is more your type than mass-manufactured items, there are a number of people out there handy with their sewing machines selling all manners of dog coats and outdoor supplies on the Internet. Ebay has 2,000+ hits on the search string "dog coat." You might want to narrow it down a bit, but if fun, funky and out of the ordinary is what you desire, you'll find it there.
http://www.ebay.com

Trixie & Peanut of NYC
If having a coat totally tricked out is more your style, Trixie and Peanut has a few interesting offerings, though I can't attest to their durability. The "personalized wrap-around fleece coat" will never let you forget your dog's name. (Don't laugh, how many times have you been reduced to just yelling, "Hey you! Get in here!"? The Adirondack jacket looks like a worthy contender in the outdoorsy category, good belly coverage and manufactured with waterproof fabrics. There are several other worthy or at least amusing coats and other pet products at this Web site. Hold onto your pocketbook though, you wouldn't want to lose your shirt while clothing the dog! http://www.trixieandpeanut.com