Hale Bopp.
I was living at 7000ft in the Rocky Mountains when it came through, a small ski town in the middle of nowhere with hardly any visible light pollution at all.
The comet was quite frankly stunning, and I really mean quite amazing. I can fully understand why the ancients got so worked up about them and thought they were harbingers of doom and destruction. The tail covered a third of the sky up there and just forced you to look at it. It was a very very obvious visitor to a night sky that is remarkable in its unchanging nature. It must have been there for months.
If this one is as good as Hale Bopp I'd travel anywhere in the world to get a good look. The view from the UK was pitiful compared to how it looked somewhere with good viewing conditions. If this new one turns out to be as good as predicted you should go somewhere really dark and see it, they are truly magnificent and psychologically quite sinister.