Malazan Book of the Fallen - Steven Erikson
Getting back into my reading a bit more lately and these books have been a revelation, 10 of them in all. Erikson may not have the smoothest prose out there, some people struggle with the denseness, especially early on in the series - but boy is he a visionary. The way he constructs this tale spanning multiple eras, unique yet all connected, is something else.
Got a few books left to go, but by all accounts they're phenomenal, so looking forward to them. Also, *cough GRR Martin cough*, Erikson pumped them all out in about 12 years.
I'd recommend them to any fantasy fan, but the caveat is they are a major mental investment, to the point where they might not be for everybody. Also, frustratingly the first book is by far the weakest (but still very good), which was originally written as a film script. Book 2 onwards though, it kicks into gear in a major way. If that had been the first introduction for new readers instead, I think the series would have taken off in a much bigger way.