Personally, I've been catching up on some classics lately. Here are a couple I'd like to recommend:

• The Book of Skulls by Robert Silverberg (SF Masterworks #23, Gollancz, trade, 223 pages, 1999, 3rd impression 2001, UK; first published 1972)
      This novel follows the journey of 4 college students who have stumbled upon an ancient secret that holds the possibility of eternal life for 2 of them, and the promise of certain death for the other 2. But who will reap which reward? It's a strange choice for the Masterworks collection, but a good one. There's very little that could justify calling this novel science fiction, but it is definitely speculative fiction at its best. It's a real treat to get into the psyche of each of the 4 young men and see how their individual fears and hopes have brought them to this ominous path.
  SF Site Review

• The Physiognomy by Jeffrey Ford (Tor, Pan Macmillan, mm, 244 pages, 2003, UK; first published in 1997)
      The shadowy and sinister world of this novel is totally nightmaric, and the character of the narrator is so thoroughly despicable (at first) that the novel is utterly compelling in that familiar horrifyingly fascinating way of the most vivid nightmares. The nightmarish atmosphere is further intensified by the drug-induced hallucinations of the narrator, which are so realistic that he's never quite sure what is reality and what is merely happening in his head. And when he does straighten things out, it's difficult to decide which is more frightening. An excellent fantastical creation, it's not hard to see why this novel won the World Fantasy Award.
  SF Site Review

Cowl by Neal Asher
Tor, Pan Macmillan (hc, 432 pages)
Publication date: 19 March 2004, UK & Canada

Mother Aegypt and Other Stories by Kage Baker
Night Shade Books (hc, 256 pages)
Publication date (forthcoming): 15 July 2004, USA

The Roses of Roazon by Cherith Baldry
Tor, Pan Macmillan (trade, 487 pages)
Publication date: 19 April 2004, UK & Canada

Judge Dredd: Bad Moon Rising by David Bishop
Black Flame, BL Publishing (mm, 256 pages)
Publication date: March 2004, USA & Canada

Cities edited by Peter Crowther
Four Walls Eight Windows (trade, 292 pages)
Publication date: 16 April 2004, USA
   A fine anthology of four novellas: The Tain by China Miéville; Firing the Cathedral by Michael Moorcock; A Year in the Linear City by Paul Di Filippo; and V.A.O. by Geoff Ryman.
SF Site Review

The Wild Wood by Charles de Lint
Tor (trade, 208 pages)
Publication date (forthcoming): June 2004, Canada & USA

Eastern Standard Tribe by Cory Doctorow
Tor (hc, 224 pages)
Publication date: 9 March 2004, USA & Canada

Letters From the Flesh by Marcos Donnelly
Robert J. Sawyer Books, Red Deer Press (hc, 191 pages)
Publication date: March 2004, USA & Canada

Medalon: Hythrun Chronicles, Book 1 by Jennifer Fallon
Tor (hc, 400 pages)
Publication date: April 2004, USA & Canada

Elvisland by John Farris
Babbage Press (trade, 323 pages)
Publication date: April 2004, USA

Swords of the Empire edited by Marc Gascoigne & Christian Dunn
Warhammer, Black Library (mm, 256 pages)
Publication date: April 2004, USA & Canada

What Price Victory edited by Marc Gascoigne & Christian Dunn
Warhammer 40,000, Black Library (mm, 256 pages)
Publication date: April 2004, USA & Canada

Cartomancy by Mary Gentle
Gollancz (trade, 313 pages)
Publication date: April 2004, UK

Daughter of Exile by Isabel Glass
Tor (hc, 365 pages)
Publication date: 8 March 2004, USA & Canada

Oceans Within by Eugene Goheen
Booklocker.com (trade, 204 pages)
Publication date: January 2004, USA

Inventing Memory by Anne Harris
Tor (hc, 352 pages)
Publication date: 8 April 2004, USA & Canada

Courtesans by Katie Hickman
Harper Perennial (trade, 363 pages)
Publication date: 5 April 2004, UK

Smoke and Shadows by Tanya Huff
DAW (hc, 375 pages)
Publication date: April 2004, USA & Canada

The Dragon Quintet edited by Marvin Kaye
Tor (hc, 304 pages)
Publication date: April 2004, USA & Canada
   Original short stories by Orson Scott Card, Mercedes Lackey, Tanith Lee, Elizabeth Moon, and Michael Swanwick.

The Last Light of the Sun by Guy Gavriel Kay
Simon & Schuster (hc, 501 pages)
Publication date: 22 April 2004, UK
   Published earlier this year in North America, and now available in the UK.
SF Site Review

Breathmoss and Other Exhalations by Ian R. MacLeod
Golden Gryphon (hc, 209 pages)
Publication date (forthcoming): June 2004, USA

River of Gods by Ian McDonald
Simon & Schuster (hc, 608 pages)
Publication date (forthcoming): June 2004, UK

A.B.C. Warriors: The Medusa War by Pat Mills & Alan Mitchell
Black Flame, BL Publishing (mm, 256 pages)
Publication date: April 2004, USA & Canada

Ringworld's Children by Larry Niven
Tor (hc, 288 page)
Publication date (forthcoming): July 2004, USA & Canada

Dreadful Sorry by Kathryn Reiss
A Time Travel Mystery, Harcourt (mm, 340 pages)
Publication date: 2004, USA & Canada
   First published in 1993. For readers 12 & up.

Frek and the Elixir by Rudy Rucker
Tor (hc, 476 pages)
Publication date: 10 April 2004, USA & Canada

Crypt Orchids by David J. Schow
Babbage Press (trade, 216 pages)
Publication date: April 2004, USA
   First published in 1998.

Moonrise by Mitchell Smith
Forge (hc, 476 pages)
Publication date: 21 April 2004, USA & Canada

Heaven by Ian Stewart & Jack Cohen
Aspect, Warner Books (hc, 352 pages)
Publication date (forthcoming): 11 May 2004, USA & Canada

The Boy Who Could Fly Without a Motor by Theodore Taylor
Harcourt (trade, 155 pages)
Publication date: 2004, USA & Canada
   First published in 2002. For readers 8 to 12.

Jaws of Darkness by Harry Turtledove
Pocket Books, Simon & Schuster (mm, 576 pages)
Publication date: 4 May 2004, UK

Secret Life by Jeff VanderMeer
Golden Gryphon (hc, 305 pages)
Publication date (forthcoming): June 2004, USA
   Short fiction collection, returning to the world of Ambergris. Introduction by Jeffrey Ford.

Dark Ages: Gangrel by Tim Waggoner
White Wolf (mm, 284 pages)
Publication date: February 2004, USA
   Tenth in the series of Dark Ages Clan Novels.

Dragon's Blood: The Pit Dragon Trilogy, Book 1 by Jane Yolen
Magic Carpet Books, Harcourt (mm, 303 pages)
Publication date: 2004, USA & Canada
   First published in 1982. For readers 12 & up.

Heart's Blood: The Pit Dragon Trilogy, Book 2 by Jane Yolen
Magic Carpet Books, Harcourt (mm, 354 pages)
Publication date: 2004, USA & Canada
   First published in 1984. For readers 12 & up.

A Sending of Dragons: The Pit Dragon Trilogy, Book 3 by Jane Yolen
Magic Carpet Books, Harcourt (mm, 296 pages)
Publication date: 2004, USA & Canada
   First published in 1987. For readers 12 & up.

Magazines

Fantasy & Science Fiction, April 2004, USA & Canada
Contributors to this issue include: James L. Cambias, John Morressy, Albert E. Cowdrey, David Gerrold, Robert Sheckley, Kate Mason, Bruce McAllister, Ray Vukcevich.

Fantasy & Science Fiction, May 2004, USA & Canada
Contributors to this issue include: Robert Reed, Sheila Finch, Peter S. Beagle, Jaye Lawrence, Melanie Faxi, John Morressy, Richard Mueller, James Patrick Kelly.

Fantasy & Science Fiction, June 2004, USA & Canada
Contributors to this issue include: Matthew Hughes, Charles Coelman Finlay, A.A. Attanasio, Joe Haldeman, Kit Reed, Arthur Porges, Ray Vukcevich.

NFG, issue 4, volume 2, Canada & USA & UK
Contributors to this issue include: Bruce Holland Rogers, Brendan Duffy, Debbie Moorhouse, Walton Golightly, plus an interview with A.C. Crispin.

The 3rd Alternative, issue 37, Spring 2004, UK & USA & Canada
Contributors to this issue include: Karen Fishler, Tim Pratt, Joe Hill, Gavin Grant, Tim Lees, Jay Caselberg, Ursula Le Guin, Robin McKinley.