When I buy yogurt, it's always plain, full-fat, and usually Greek style. My preferred brand is Skotidakis, which is not sold by Whole Foods. I buy it at a local market here that sells Greek products. They sell many types of Greek yogurt. I flavor and sweeten to taste. You're not supposed to eat it plain unless you like it like that, so it's not fair to say that they taste awful because they're no sugar. Plain yogurt is meant to be flavored whether it's for sweet or savory. It's what you're going to use for cooking and baking. Best yogurt I had was house-made by a cheese shop. It was Greek-style and goat's milk. It managed to surpass Skotidakis!
Also had great ones from the farmer's market from a few different vendors. If you have places like this, check them out!
I also like labne/lebneh/lebni, which is basically the Middle Eastern variety of Greek-style yogurt. This is also not sold at Whole Foods, but rather in places with any sort of Middle Eastern population.
Brands sold at Whole Foods depend on where you live. Maple Hill Creamery makes really nice, lightly sweetened yogurt. Liberte is a good brand as well. Brown Cow is said to be good. These are not Greek-style, but I'd hardly say they're runny. They're simply normal whole milk consistency. I never buy low-fat yogurt, so I don't know if they sell low-fat versions and what they're like. For Greek style, Fa-ge is easily found and I think they sell some sweetened yogurt as well. Oikos is another Greek-style yogurt. Iggi's makes skyr, which isn't really yogurt, but is marketed like it. Theirs is lightly sweetened and has no stabilizers.