I think there is a difference between ocean fish and lake fish - halibut, snapper, fresh tuna, salmon, have less of a "fishy" taste to me than something like catfish. The key is freshness. If you don't live near an ocean you might do better looking for frozen fish. And try different grocery stores - ones that define themselves as more "upscale" tend to have better fish selection. Frozen prawns are also a good alternative.
For salmon, I like baking it slowly covered with foil and with slices of lemon on it. Fresh tuna is good peppered and seared in a pan. Don't cook it too much - it is best almost raw. A whitefish like snapper or tilapia is good baked in parchment with chopped tomato, onions, and herbs. It is lowfat, and the acidity of the tomato and the flavor of the onion counters the "fishy" flavor. The parchment keeps the juices in, which then can be soaked up by brown rice or something like that.