I would recommend Tromso in north Norway. Book a tour with local guide Kjetil Skogli. He's not the cheapest but is worth every penny. He takes you out in a small group (6/8 maximum) in a minibus anywhere where the weather will be clear – other companies have a fixed base somewhere near Tromso, so if it's cloudy there but clear 30 miles away then tough!
One hint to photograph the aurora: take a tripod, a fast wide lens and a camera that will let you use long exposures (10 to 30 seconds) with a remote cable to avoid camera shake.