Do I need a dog?

Yesterday at work SB's husband brought in a female Jack Russell Terrier and showed her off at the back dock of the library. I must admit the dog stole my heart and, to make matters more interesting, a couple of my library coworkers were trying to convince me to adopt the dog. I gave it some serious thought last night.
When I came into work today, I was happy to hear that SB and husband decided to take in the dog with their other two JRTs. SB says that all three dogs managed to accept each other with minimal growling. Jack Russels are energetic dogs who command lots and lots of attention. Since I have a long commute to work, that would mean that if I had a dog I would leave him alone for about ten hours. I don't think a JRT would be well suited to my house as well as my work schedule. A shame--that dog was adorable.
Perhaps a dog that naps during the day or needs less attention.
Perhaps a cat.....