Norway is probably your nearest bet. Maybe Northern Iceland. If you are prepared to wait a few years though this may be best. The sun is at the lowest point of of the solar cycle meaning it is least active at present. This means less frequent and less spectacular aurorae. The cycle is approximately 11 years long. The graph on the bottom of this page shows when the next predicted maxima in the cycle will be.
http://solarscience.msfc.nasa.gov/SunspotCycle .shtml
After having a quick look at the other site though. I think as long as you spend a week inside the Arctic circle in winter, good weather permitting, you should get at least one showing.