I agree, get the dog sooner rather than later and make sure it is well socialised. Get a dog that you can manage in the space with all the stuff that goes with kids too - its amazing how small your house will feel with a pram, a bouncy chair, a crawling baby and a dog!
Decide where the dog will be allowed from day 1 and put up gates where necessary. I had two dogs when dd arrived and from when I found I was expecting, a stair gate went on and we started excluding them sometimes from the living room - they got used to this before baby.
At the 7 months mark, I started carrying around a doll wrapped up and pushed them away from me, throwing a treat for them and teaching them to 'go settle' - they picked this up quickly and learnt when I had a bundle, I ignored them. I also got a tape of a baby crying and playing this a bit, both upstairs and down, so they desensitised.
When dd was born, OH brought home some babygrows and let the dogs sniff them, placing them on a chair in the kitchen and living room, so the smell became familiar.
When I came home, I put the carrying seat on a bench outside and let the dogs (a terier and a BCollie), sniff it -dd moved and the collie jumped back a mile!!! I made sure I gave them a lot of fuss.
For us it was fine, we were always careful, but the preparation had made it easy (one of my dogs was a rescue with a history of biting, so I was very careful), both accepted her as part of our family group and never so much as growled at her, she learnt from an early age to 'respect' dogs.
When she was 2 and the old collie had died, another dog came along, I would never have thought this was a good age to have a dog with a child, but I was wrong, the dog - the sweetest I have come accross - and dd bonded, they are now (she is 7), best buddies in the whole world and it is ajoy to see.
Common sense and understanding how dogs think is the key. To be honest, I would be more worried about where the dog is going to be when you are at work!!!!
Best of luck with your family - dog or human!