I'm not being facetious when I say that I am ASTONISHED that nobody has mentioned George RR Martins 'A Song of Fire and Ice' series.
Absolutely 'adult' fantasy. Not for kids. The only drawback is that he is a bit slow in getting to the next book (which I am eagerly awaiting), but it's hard to complain when the quality is so high.
They are in preproduction for an HBO series based on the novels, they have won most fantasy awards, have spawned a card game, a role playing game, minted coins, artwork, miniatures and more.
Check it out.
Eric