Most of the chocolate I eat is 70% cocoa or higher. My favorite brands are Amedei (Porcelana and single origin "Cru") and Green & Black's. I like most of Green & Black's dark chocolate (and their milk and white chocolate were my some of my favorites before I became a vegan... their white chocolate is strong on the vanilla, almost like ice cream). I just tried their Orange bar yesterday, it's excellent. Amedei is too expensive for me to eat more than once or twice a year, though.
Lindt is also good and used to be my favorite easy-to-find chocolate (most grocery stores and supermarkets carry them), but at a similar price and availability I prefer Green & Black's more now. I also like Nói Síríus (70% bars). I often have a bar of that in my desk drawer at work and will eat maybe 1/4 or 1/3 of a bar in a day at most. People balk at the price of good, high cocoa/cacao percentage dark chocolate, but you don't have to eat anywhere near as much as cheap milk chocolate bars. You get richer and more subtle flavors to savor rather than just the sugar of a cheap Hershey's which is easy to just eat a whole bar in a sitting. There's nothing wrong with liking Hershey's (hey, I like plenty of regular candy), but it has very little cocoa flavor in it. It's marginally chocolate, in my opinion. There are numerous health benefits of dark chocolate, as well, that you don't get from the vending machine bars.
Valrhona also makes some really good chocolate, but I've only tried their milk chocolate and one dark chocolate bar (can't remember which variety) once a few years ago. I need to order some more chocolate from them. Guittard is probably my favorite brand for baking/cooking and for drinking chocolate (hot chocolate).
I've also been making my own chocolate lately. Made some dark chocolate 2 weeks ago and mint matcha white chocolate last week. Both turned out delicious. The next day I turned some of the latter into chips (well, chunks, really) and made some matcha mint white chocolate chunk cookies with them. Mmm.