Bonti

As the other reviewers mentioned, Bonti is probably the most expensive baby store in Stockholm. However, they also have the best service of all baby stores in Stockholm — the ladies who work there are kind, helpful and actually know what they are talking about — they can answer any question you have about any car seat, pram, or other rather expensive item you will be investing in for your child.
They are also the only place in this entire city who have a service to fix broken parts on prams. Our brake on the bugaboo got stuck, we took it to 3 bike shops and a couple baby stores (baby profesen, etc) and no one would touch it, they all wanted us to buy a new Bugaboo frame… finally, I took it to Bonti and they have a buggy technician who you can make an appointment with and he will fix anything/​everything he can for a small fee. The brake operation cost just 100 SEK.
A great place for baby presents as well! They have beautiful items.