A lot of good advice in this thread already.
We had a similar situation, where we both worked and had to leave our pup home during the day. Our breeder actually potty trains her dogs to use a litter box. We used to fill it with feline pine, which is basically little pine logs. So we continued with that and then started transitioning him to outside when he was ~9 months to a year old. We still left the litter box around for probably a year and a half to two years until he stopped using it during the day while we were gone. After a year or so, he really didn't use it unless we were running really late. Once he stopped using the litter box during the day (for something like 3-4 weeks), we finally removed it. The stuff clumps, so you do not have to empty the whole thing every day. It was actually pretty easy to transition him to outside as you just use some of the dirty feline pine to show him where you want him to go.
So we crate trained our dog for at night. But did not leave him in his crate during the day. We thought that would be tough on him to spend 20 hours a day in a crate. So we setup an x-pen in our family room. We bought one of these:
http://www.amazon.com/Pet-Yard-Plast...uct/B000633XHS. We put a doggy bed on one side and his litter box on the other (basically a plastic container bottom for storing clothes under the bed). To protect the floor, I bought a $30 piece of pre-cut laminate flooring from Lowes/Home Depot.
We actually still use the xpen set up and he is now 6 years old. So we do not let him run around all day while we are gone or go out to the store. I think he is actually more comfortable in a confined space as opposed to running around not knowing if we are home. Of course, our dog is a small to medium size (~20 lbs). A setup like ours would not work for a larger dog.
At first, we tried to have him sleep in his crate in the x-pen, but that did not work. He whined all night long. Once we moved his crate into our room, that really helped. So his crate still sits in the corner in our room. We have a Cavalier King Charles Spaniel. Great dogs, very loving, easy to train, but very needy. They are not independent at all. You can also not take them off leash as they are not smart enough to not chase something into the street. You also want to make sure to get them from a reputable breeder or from rescue as they can have health issues. They are also not cheap from a reputable breeder.
A couple of things I would consider before getting a dog from my experience (he is our first and only dog):
1. Do you like to go out at night after work?
2. Do you like to go on frequent vacations?
If either of these are a yes, I would really make sure getting a dog is something you want to do at this point. It is really tough to go out during the week when you know your puppy has been home alone all day for 8-10 hours. We did not start going out during the week until I started working from home all day. We take our dog to a local breeder when we go on vacation. So we basically need to check on her availability before we book a vacation. It is also a lot harder to take a last minute trip. Now this could just be us, like I mentioned, Cavaliers are really needy, so we don't like the idea of taking him to a traditional boarder where they stay in crates or rooms all day long.
For us, I can comfortably say this is our last dog. I love my dog, but having a dog is a lifestyle change. You always have to think about their well being. (I know some people leave their dogs outside all day with a dog house and food/water, which is fine, but that is not why we got a dog). Plus, having children has really been tough on our dog. He is no longer child #1 and that has been tough.
Remember, they can live 9-15 years, so just think about that in terms of now versus the future. I know you can always find a new home for them, but I don't think most people consider that when they get a dog. Also, we buy a lot of lint rollers and have to vacuum often. Just something else to keep in mind. ;-)
Also, there are a lot of little expenses that add up. If you live in an area with fleas, you are looking at $15-20 a month for flea medication. At first, we bathed and groomed him ourselves, but when we found out we needed to express his anal glands once a month, we started taking him to a groomer (cheaper than having the vet do it). So we probably spend $100-150 a month when you add in food, treats, grooming and flea medication. Not to mention if he gets sick or is not feeling well, the vet is not cheap. We also had to have his teeth cleaned when we was 4-5 and that was $800-1000 (I live in the Bay Area, so things are on the high side).
If you get a dog, I recommend brushing his/her teeth everyday. We didn't do it and now our dog hates it. It will save you some expense down the road.
Finally, we get premium dog food. The better the dog food, the better their stool is, which helps when you are picking it up. lol