The MacPaws is an excellent idea, a sort of pac a mac for dogs, that folds away in seconds into a tiny little bag that has a handy clip on it.
They come in a great mix of colours so there's something for all tastes, and they've even used very nice shades such as the pink, it's a lovely pastel pink and not horribly garish like some others.
The velcro straps mean they fit easily on the dog, they're perfect and lightweight for getting caught in showers, and they didn't restrict movement on the dog at all, though they're not thick enough for a proper downpour.
A handy flap at the back of the neck means you can still have a harness or collar on underneath the coat too. A definite must for dog owners, great as a little handy compact for when you get caught short in the rain.