I love a nice plate of cold water Atlantic oysters, with a gin martini or crisp sauv or fume blanc. Blue Points and Wellfleets are my favorites, though Matunuck and Watch Hill and several others here in RI are quite nice.
Oysters are part species, and part terroir (or merroir?). All oysters on the east coast (including the gulf) are the same species (C. virginica), with variations in taste and consistency based on local growing conditions; an overwhelming majority of them are farmed. Pacific oysters (C. gigas) are common around the Pacific Rim, but to my taste lack the minerality of the northeastern oysters I enjoy most; Pacific oysters have been at the center of my most disappointing oyster experiences. There has been talk of using gigas to clean the Chesapeake, but there are fears about introducing species. Kumamoto (C. sikamea) are farmed primarily in the Northeast; delicious, but hard to get around here.