Well, I did have some ideas. First, I had figured, by fiat, that our island's latitude would be roughly that of North Carolina. Secondly, it would be nice if we could locate it along with a geographic feature on the ocean's floor - a seamount or something similar.
35 N is roughly equal to the southern border of North Carolina. The climate there is fairly mild, and would be more so that far out to sea - snow would basically be unheard of, as would frosts.
At that latitude, there are no real sea features to speak of once you're off the Continental Shelf until you reach about 57 W. That's the end of a series of seamounts - an underwater ridge - which extends northwest until it meets the Shelf off the coast of Nantucket. There is a nearer formation at about 33 30'N, 62 W, which places it very close to Bermuda (167 mi/270 km).
Beyond that, 35 N features a series of uneven features from 53 W to about 47 W. You encounter the Mid-Atlantic Ridge at about 35 W; at that point, the Azores are about 425 mi/650 km to the northeast.
Personally, I'm in favor of about 35 N, 57 W - the location of the little pin I put in Google Earth is 34 40'21"N, 56 42'37"W. That puts us a very good ways out to sea:
- Distance to Bermuda: 479 mi/770 km
- Distance to Sable Island: 660 mi/1062 km
- Distance to Halifax: 773 mi/1243 km
- Distance to Boston: 934 mi/1502 km
- Distance to New York: 1029 mi/1657 km
- Distance to Virginia Beach: 1086 mi/1748 km
- Distance to San Juan: 1258 mi/2024 km
- Distance to Ponta Delgada, capital of the Azores: 1740 mi/2800 km
- Distance to Lisbon: about 2630 mi/4225 km
- Distance to Casablanca: about 2800 mi/4500 km
- Distance to London: about 3000 mi/4800 km