I guess if you know you will be doing the work, it depends on how much you can handle. We have three labs, two cats, fish, and turtles, and 3 kids. I take care of them all. One dog is my DH's hunting dog, but I still take care of him. I would say NO! to another pet because I know even though they say they are going to help out, I know its not ever going to happen. My two older kiddos do help out with the pets when they can though, like letting out and feeding, but its mainly me. And we have a fourth kiddo on the way. I am able to handle it all because I am at home all day. If we both worked, I wouldn't be able to handle another pet. So, I guess it all depends on what you can do.
ETA: I also agree about the doxies around young children. Almost every one I've met or known someone who's had them they aren't good with kids. Having one that is seems to be the exception. My inlaws had two of them and I wouldn't leave my children alone with them when they were small. They were nippy and moody around the kids. Not the adults though.