We are definately thinking about getting a dog.  Question is what sort?  Needs to: get on with cat and not be too fiesty as we also have two rabbits; like a good run - Im not a walker and between my husband and I we think we could take it running once a day then for a good walk once a day maybe 1 and a half to two hours a day more at weekend; be quiet when left; we live in a fairly built up area but there are still plenty of open spaces; gets on with people as we often run with friends.  Not too big as our house is a cottage.

Do you both work full time?

I suggest you make a list of traits the dog must have, and more importantly must not.

for example in my

must have:

Must be sociable
Medium size
Have a nice coat
Sensible but lively character

Must not:
not have floppy ears,
Jowls or slobber,
not have a flat face,
not have very long or short coat
be overly excitable or clingy
be too big (over 24inches at shoulder)
Too small (under 18 inches at choulder)

When you have done this go onto the Kennel club Website and go through all the breed standards listed (some Groups you might not expect may still have the dog for you).

I then suggest you attend a show to meet a shortlist of breeds and their owners to get more of a feel for them, there are a number of Championship shows coming up, and also Discover Dogs in November in London.

when you are down to say two breeds contact the breed club secretaries and see if you can arrange a visit with owners of the breeds. 

Meet them in their home and ask to go for a walk to see how they are out and about, around other dogs and people.  This should tell you if the breed will be one YOU can live with.  One mans meat is another mans poison.

Avoid going to anywhere that actually has puppies at the moment as pups of any breed are hard to resist.  You don't want to make a decision based on heart ruling the head. They don't stay puppies long.