Stockholm-Arlanda has almost anything that you may need for your trip. You can find luggage in the various Fashion shops, cameras or extra memory cards for digital cameras in Electronics in Terminal 5.
Samsonite
You can find luggage and bags from Samsonite in several different colours and models in the Fashion shops. The Fashion shops also have other items that you may need for your trip. There are luggage straps in several different colours and models; there are neck cushions, earplugs and eye-patches that will make your trip more comfortable, and there are also money belts and shopping bags in different sizes as well as umbrellas if you should need one.
Electronics
Extra memory cards for cameras, chargers for mobile phones, adapters, etc. You will find all this in Electronics in Terminal 5. The staff is very knowledgeable and can assist you in finding what you need. You can also find CDs and DVDS that will make your trip seem shorter.