I don't have one

, but the little gold $2 (1865-1888) stands out to me.
No-one else in North America was issuing anything like them at the time, and India and the Australian colonies were the only other parts of the British Empire issuing gold. Most are "common dates" and, according to Krause, fairly cheap (US$150 or so in VF) but 1880 is the key, and seems to be the most sought-after Newfoundland coin. There's even an extremely rare 1880/70 overdate to look for.
I find the design interesting, too - a triple-denomination: 2 dollars, 200 cents and 100 pence.
As I said, I don't have one, so if you'll excuse me, I'm going to go and edit my wantlist to include it...
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis