I just finished Tim Powers's The Stress of Her Regard, and it's awesome.
I bought it from Jacob Weisman of Tachyon Publications at WorldCon, and had a nice chat with Jacob about selling strategy and about what literary fantasy is. The Tachyon edition is, frankly, beautiful, and if you're going to buy this book, which you should, buy their edition -- it's got the gothic font on the cover and the picture of the guy raising his arms to a Swiss alp (Mont Blanc? not sure...).
Tim Powers has a great shtick. He writes speculative fiction in the gaps around weird historical events. In the case of this book, he's written a vampire(ish) story around the lives of Keats, Shelley, Byron, et al. This approach makes the book more rewarding the more you know about and like the events and historical figures that are treated, and that probably makes a book like The Stress of Her Regard eminently literary fantasy (horror).
There's a cost. Since Powers doesn't compromise on the known historical events, the plot has to bend to fit them. In the case of this book, it means that the pacing is sometimes rambling. An interesting barrage of events happen... and then years go by before the characters decide to do the next thing.
Still, five stars, two thumbs up, can't wait for the movie... ha!