If it's just you and don't work at home or aren't in a position to be home most of the time, DON'T get a dog. Dogs are very social animals, and I personally think it's cruel to have them cooped up all day while people are at work. If you can afford "doggie daycare" or want to get two dogs and have someone walk them during the day, that's preferable.
We didn't get our pup until my wife could stay home with her. We've been rewarded with the sweetest dog around, and she's absolutely wonderful with our two year old despite having her ears pulled and being walked on. The dog is 80 lbs so she enjoys a certain size advantage over our 24 lb daughter.