Haven't stayed at any of these yet, but we did book the Quality Inn Arlanda for our trip in July. These 4 were the one's we were looking at before our group decided on the Quality Inn. Note-Prices all ranged from $130-$180 for the dates we looked at.
Radisson SAS-There is also one inside the airport, but was much more expensive. Had free airport shuttle.
Quality Inn Arlanda-also free shuttle
Hotel Connect Arlanda-Seemed a bit below the quality of the above 2. Charge 100SEK for some shuttles
Arlanda Hotelby-Set up like a small village. Seemed like it would be a different type of place to stay.
The person we're visiting in Stockholm recommended the Quality Inn or SAS. Hope this helps!