It sounds lovely that you're thinking about getting a dog. 
A few points. Allergies - NO such thing as a NON shedding dog - just a dog who sheds less than others. Sometimes the allergy is to the dander rather than the hair so you need to find out what triggers you/allergic person. Try to be around/handle a variety of dogs (both long and short haired) to see what triggers you. What would be utterly heartbreaking for all of you is to get a dog and then find that allergies mean you can't keep it. Sadly, this does happen quite often.
Housekeeping - if you are really, really houseproud please don't get a dog. Even a small dog will shed, occasionally wee, poo, vomit, bleed, walk in odd things, roll in odd things, smell, fart etc. Could you be prepared to think of dog hair as a condiment? Please visit some dog owning friends and think about their standards of housekeeping and what you'd be happy with. Not just the house, but the garden and the car too. Car will get dog hair, mud, smells etc. Garden will have plants wee-ed over, holes dug, small plants trampled, poo deposited. It is possible to have a clean tidy house with a dog (or three) but does take a lot more work, especially at this time of the year, when everything outside is wet and muddy.
One of the things you could do before getting the dog, is to go along to some doggy events and chat to people. Most areas have regular events like fun dog shows, walks, open days for charities, etc etc - go to events, have fun, (most important!) and chat to people about how dogs fit with their family/lifestyle, and any other questions. The more time you spend in this type of preparation, research, the better informed you will be, and the more likely to get a dog that is right for your family. Have a think also about once your dog arrives and what you will be doing with it, as a family. Taking it to basic obedience classes (and puppy classes if you get a pup) is essential, but there are lots of other fun things, like Cani X, agility, flyball, obedience classes, geocaching etc. Most of these activities will have clubs/groups locally and it's worth going along to find out more.
With regard to the small dog/big dog thing, it's surprising that the impact of the dog when you live with it is not so much to do with size as temperament. A very small JRT with no "off switch" will make its presence felt far, far more than a larger, but very quiet greyhound who just likes to snooze on the sofa.
Lastly, before you get ANY breed of dog take a look at this terrific website - Dog Breed Health here. It gives an honest look at the health issues, health testing and diseases associated with particular breeds. It's a mine of information, that every potential dog owner should consider when thinking about breeds. One of the reasons why I regularly recommend greyhounds for instance is that they are generally v healthy and can be expected to live to their mid teens. Their COI score is 0.7% (score for inbreeding) - for a bulldog (as recommended upthread) the score would be 9.9% and the list of illnesses/welfare problems associated with the breed is long and depressing.
Good luck! 