Coriander is the seed that if grown is usually called cilantro in Canada. I'm one of those who think cilantro tastes like soap, so I always substitute parsley. I'm actually OK with the seed though, but would use it in pickles or savory dishes.
Cardamom is a spice I use in Peperkakor cookies, so I suspect that's the one you're looking for - but I do not drink coffee - don't even like the smell of it - total tea granny here and I do have teas that cardamom would be great in.
Like Jordan, I'm going to have to try both. Cardamom in coffee is classic (tea too, think of chai) but I could see coriander seed as well- I make beer as well as tea with dry coriander seed. People put much stranger things than coriander in their coffee!!