I'm a big Laphroaig fan, but Lagavulin is my go-to favorite. They are fairly similar and located pretty close to each other. If I recall correctly, they actually shared facilities for a while and there were some lawsuits over some alleged stolen recipes.
I love the peat and smoke. I can't remember which one I was drinking, but one day my wife came home from work and asked me, from across the room, if I had been smoking. No honey, just drinking some scotch.
If you really want to get into the seaside flavor, get some Talisker Storm. I swear it tastes like the ocean.