Aurora are somewhat difficult to get good pictures of. Basically you need a camera with very good low light capability and/or a "fast" (wide aperture) lens. They're also big, that you need a wide *angle* lens ideally as well. I had an f3.5 10mm (15mm on crop sensor) that I used for most of those shots and it worked quite well. Would have been nicer to have f2.8 or even f2, but that kind of lens (if it even exists at that wide an angle) would cost a lot more than my 10-20mm. Having a camera with very low noise high ISO capability also helps a lot. Mine is decent but not exceptional. Someone with a Nikon D700 or D4 would probably be able to capture some really stunning stuff.
Russ, sorry I missed you! Had no idea we had a TG-er in Fairbanks, but I suppose I shouldn't be surprised. We did really luck out on seeing the aurora while we were there, mostly from Ester Dome (so yeah, I think you nailed the viewing location).
Anyway, I will be back, Alaska definitely won me over. I want to return for more aurora viewing of course, but also would like to check it out in summer when everything is green, and ride the train from Anchorage to Fairbanks (through Denali I think). That sounds amazing. Also glaciers!