There really are so many pros to having two dogs, that once you have more than one, you really never want to settle for just one again. I would have to search for the info, but we've discussed this on the eskie board often, as they are just as addictive. Some of the arguments I recall:
Against:
higher cost- yes, vet bills in particular are higher....basically double. Food costs are more....again basically double. You'll have to buy more toys, another crate, carseatbelt, leashes, collars, etc. that you normally use. You'll also have to either do more grooming yourself, or pay to have it done.
For: Everything else!

Really, the joys of more than one are awesome. You have two bundles of love to enjoy every day. They often can keep each other amused and active, and not require you to be as involved.....though you can still be just as involved and play with both just as much. Just that when they want to play by themselves, they often will. This often means more active, healthier, happier dogs, as they don't laze around as much, or *have* to look to you for attention, as is the case with some single dogs. Once you see two dogs really enjoying each other in your home....it's over...you'll never look back!
Concerns: Exercising and taking care of two dogs is really not as much work as some might think. It's not really double, but just a slight increase from one. I mean, you are already taking one dog outside when you go, taking two isn't much more effort. It does help if you can each walk one of the dogs, as then not only do you each have one dog on a leash, you are spending time together yourselves. If one person needs to walk both, yeh, it can be a bit more work, but again, not much more than one. You either use two leashes or have a coupler to split the end.
But, I'm a true believer in dogs having siblings any more. Jamie was very much an only dog.....she and Shelby never really "bonded" all that much. And it was mainly because Jamie was a daddy's girl....I was the love of her life, and so Shelby was just a sister. Still, I could tell they appreciated having each other around, so it really was good in the long run. But Shelby couldn't stand being alone, and she's great with Amber. These two actually play and goof around a lot more and it's great to see. Amber's used Shelby as a pillow lots of times, and it's just precious to see them sleeping against each other. I know neither one of them would want to be alone these days.
Oh, one other thing....and this is more for "you". When you have more than one dog, one will usually go before the other does. And it's harder to lose an only dog, because you don't have any other bundle of fur around. But if you have more than one, it actually makes that loss easier. When I lost Jamie, I told Shelby's breeder about it (it was right before a show weekend, so I had to skip the show), and she wrote back and told me to take care and that Shelby and I would need each other right then. She was right! We did. So, if that matters to you, it's another thing to consider.
Anyway, just some more food for thought on that.