In reply to James Rushforth:
I though Night's Dawn started out well, and went progressively downhill, which is a real shame. I've come to the conclusion that I don't really like any of PFH's other stuff.
Charles Stross has done some good scifi... Singularity Sky was entertaining, if quite lighthearted (its sequel, Iron Sunrise was neither as lighthearted nor as entertaining, and the author has abandoned the universe). Accelerando, Glasshouse (both set in the same universe and sequential, though you don't need to read one before the other, really) and Saturn's Children (and to a less extent, its sequel Neptune's Brood) are all pretty good.
Alastair Reynolds' Revelation Space books (of which there have been quite a few) are jolly good. I haven't liked all of his other stuff, though... Pushing Ice wasn't bad, Blue Remembered Earth was good, but the sequel On The Steel Breeze didn't work nearly as well as any of his other books.
I really liked Ken MacLeod's Fall Revolution books (near future technological singularity etc etc), but I didn't like any of his other work at all which is a bit of a puzzler.
Richard Morgan's Kovacs' books aren't bad, though they may not be quite what you're after. The first one is very much a film noir homage, though the later ones are more conventional pulpy scifi with some clever things thrown in for good measure.
I've read Ancillary Justice and Ancillary Sword by Ann Leckie and liked them... the scifi awards people loved her work, but I don't think she's the new Iain M Banks by any means.
Oh, and for slightly older-school but very-clever-for-its-time stuff, have a look at Schismatrix Plus, by Bruce Sterling. He isn't the easiest author to read, but he's had some amazing ideas, and generally has them years ahead of more 'mainstream' scifi folk.