Amazingly poetic, thoughtful and descriptive writing in all of his work. As Nate mentioned, The Fionavar Tapestry is a good series but not his best work. I would recommend starting with The Lions Of Al-Rassan which is a stand-alone novel and is one of the 5 best I have ever read. It is roughly based on El-Cid and the fun in Moorish Spain. No magic, just war and politics and it will make you laugh and cry and cheer. So start there if Kay is the choice...you can then move on to The Sarantine Mosaic which is a duology set in the same world but with different characters.

Abercrombie is a completely different style of author. In your face, brutal and quirky. The First Law Trilogy is his first published work and it is a terrific start. The characters drive the story but that doesn't mean it is lacking in plot. It is more traditional fantasy (barbarians, magicians, kings and their successors) but the focus is on the background players and it is exceptionally done. Not for the faint of heart though, there are some really nasty torture scenes in the books as one of the main points of view is from a former soldier turned "inquisitor" after he was brutally tortured during a prior campaign.