My three favorite cheeses - don't ask me to rank them - are Grafton's four year cheddar, any three year gouda (Beemster was the first I had), and Humboldt Fog. If I were to expand that list, I'd include Pecorino Romano and Parmigiano Reggiano, more cheddars, Cotswold, cave-aged Gruyere, aged Manchego ... all of which makes Humboldt Fog stand out even more, because unlike all of those, it's a young cheese, and a mold-ripened cheese. Mold-ripened cheeses usually aren't my thing at all, and young cheeses are fine - I like goat cheese - but (with one other notable exception, Vermont Creamery's Bonne Bouche) don't inspire a lot of passion in me.
Humboldt Fog is pretty amazing. It's so amazing that it's become cliche to say so. It was one of the first cheeses I heard of in the slowly growing discussion of "American artisanal cheeses," and won a bunch of awards starting in the late 90s. Even before the current trend of certain restaurants listing the brands and provenance of their ingredients, restaurants were making a point of offering Humboldt Fog stuffed figs, or omelettes, or cheesecakes - not just goat cheese.
It's a goat's milk cheese, with a line of ash running down the middle like (cow's milk) Morbier. The interior is like fresh goat cheese - nice and goaty - with a layer of soft-ripened (Brie-like, if that makes more sense for you) cheese surrounding it. The bloomy mold is tasteless, which is probably why I don't mind it.
All in all, I keep telling people it's like "goat cheese cubed." It's not that there are flavors here you don't associate with goat cheese, as such - but they're stronger, more complex, more nuanced, more powerful. It's a smoker's cheese, I suppose - I'm not anymore, but am aware that a lot of my food loves (rich braised meats, whiskey, spicy food, aged cheddar) come from having smoked moderately to heavily from 18 to 28.
Like any other goat cheese, it goes great with grits - or in an omelette, or with prosciutto, chorizo, or salami. I've never tried it on pizza, but I really ought to.