HMC I have a dog, a springer spaniel and TBH I wish I didn't I love her to death, but she is really my dh dog. However when we got her dh could walk her everyday, now he has a full time job and so do I. She doesn't get the walks she should. Before you all scream at me we have a nanny who is there most of the time and lets her out, or the next door neighbours do, and in summer we don't shut our door so she is always outside.
The mess that she makes is incredible, I don't have high standards but I have to hoover twice a week to keep the dog hair under control. We are so limited if we go out as to what we do, both for single days out - we must get home for the dog, and for holidays - where can we go that is child and dog friendly?
Actually that is the key, you maybe a responsible dog owner, but others aren't which means all beaches and play areas are banned for dogs, our local park bans dogs in certain areas, so the kids cannot go on the play ground, as we can't take the dog there. The fenced of play areas are alright, but the dog has to stay outside the fence. Holidays like camping would be fine, but often teh good child friendly campsites ban dogs, and most beaches ban dogs for the summer months. We are very lucky as MIL owns our dogs mum, therefore whenever we want to go away without her, she can stay with them. But do you have this, or are there good kennels locally? To me this is the biggest problem with dogs, we can't even go for a nice long Sunday walk and a pub lunch, as teh dog is barred form most pubs!!
If you are prepared that you will have to make arrangements for this sort of thing, then fine, but these were things we didn't think about when we got the dog, so I am afraid she spends a lot of time at the in-laws. One time when DH was away with a job she had to be with them for 4 months!!
Think very very carefully, particularly if your dh isn't keen, as it is more hassle than having kids at times!!
I can't suggest a good breed of dog as I think each dog is different, our springer is great, soppy and even doesn't care when my girls put fancy dress outfits on her (they are 4 and 2), but she has been around for 7 yrs and is used to them. She was a little funny when they were born however. I would be tempted to wait for a while to get used to having 2 kids before you decide you can cpe with a dog. I found the jump form one to two was far far more work than form none to one!
Good luck, sorry to ramble!