Hotels in Stockholm

I stayed at Hotel Adlon in October 2009. It was nice. I think around $200 per night, not sure if thats medium or not? Hotel was nice and clean, front desk was helpful, spoke excellent english. the breakfast was good. The have a nice downstairs lounge area with a public computer and they also have wifi. Its only about 3 blocks from the train station, and an easy walk to Gamla Stan and the main downtown harbor area.
There's a station for the airport shuttle train only about a block away. Lots of shops and restaurants nearby, and a couple small grocery shops.

You may want to visit Tripadvisor.com. It provides lots of reviews for hotels, maps their locations, gives prices and allows you to book directly from there. I've booked through them multiple times and haven't had a problem yet.

If you are driving there is an Ibis outside the city in the burbs that is within a short walk of the subway. Good breakfast for a reasonable additional fee and free parking.