Honeycrisp apples are a cross between a Macoun and a Honey Gold. They’re advertised as “explosively crisp” and they are! Oysterspearls enthuses: “So juicy that you have to bend over as if you’re eating a ripe peach and with layers of flavor that I’ve never seen in a apple. Hints of pear and wine.” Hoagy294 found they’re good for baking, and hold their shape pretty well, but this is an apple than really shines when eaten out of hand. They don’t seem to keep as well as some varieties, so try to buy them from a grower for the best example of this apple.
Robert Lauriston recently discovered Pinova apples. He says they have great flavor, and have “an adult-oriented balance of sugar and acid”. It’s a firm apple and a good keeper when it’s kept cold.
The Opalescent is one of the excellent “antique” varieties. LindaWhit describes them as larger than the average apple, and red with a bit of yellow or green in the skin near the stem. The taste is complex: it’s initially semi-tart, with nice crisp bite, followed by sweetness. Here’s a picture.
For a sweet/tart apple, Karl S recommends Winesap or Baldwin. Good tart apples are Pippins, Granny Smiths, and Russets. For the best experience, buy apples near where they’re grown.