I finished the 4th "blockbuster" fantasy book of the year Bloodheir by Brian Ruckely - I may come up with a review soon, and I read 3 blockbuster sf books too, so already it's crowded at the top of my list and a lot of books are still to come. This year I am keeping count of new books - for me - read, and I am currently at about 68 novels done or almost done and a lot of anthologies/magazines and quite a few of extra short stories. The novels are split 28 sf, 20 fantasy, 20 historical/mainstream though classifications are tricky.
Looking at only 2008 releases from now on.
In fantasy the 4 2008 blockbusters I've read would be ranked as follows:
1. The Kingdom Beneath the Waves by S. Hunt - can move to sf easily
2. Bloodheir by B. Ruckley
3. LAOK by J. Abercombie
4. The Red Wolf Conspiracy by R. Redick
Rounding them, there would be 3 excellent novels, Shadowbridge by G. Frost, Ninth Circle by A. Bell and Passage by Lois Bujold - all these I've enjoyed a lot but they lack the epic quality of those 4 above, so it's hard to make a comparison
In sf I've read 3 2008 blockbusters:
1. House of Suns by A. Reynolds
2. Line War by N. Asher
3. Matter by IM Banks
Rounding them would be the excellent Martian General's Daughter by T. Judson - this one was so unexpectedly good that I am tempted to break my habit and rank it with the blockbuster epics above. Then excellent too would be Death's Head 2 by D. Gunn, Slanted Jack by M. VanName, The Great Planet Robbery by C. DiLouie, Earth Ascendant by S. Williams
Ahead there are several more blockbuster books coming and others with lots of potential , so this year will be very crowded in my top 10 lists...
In SF to come: BSRA by D. Weber and maybe even an arc of Storm of Shadows late in the year, and maybe another for Crown of Slaves 2. Anathem by N. Stephenson. Implied Spaces by WJ Williams. Incandescence by G. Egan. Void 2 by P. Hamilton. Space Opera by M. Flynn. Possibly AI War by DK Moran. All blockbusters or potentially so... And then Cosmos Incorporated by M. Dantec and Neuropath By S. Bakker may get to that status in my eyes due to their controversial content. I am not sure about Stross novel Saturn's Children, it may be just another geek novel, but the blurb looks very interesting - still I have not read a blockbuster novel from Stross yet, so we will see. Also A. Remic's Biohell, Ketos by P. Palmer, Multireal by DL Edelman may compete there as well as the new 163* saga The Dreeson Incident. also Jack McDevitt has a new Alex Benedict book, and while none of the recent Benedict books approached the brilliance of a Talent for War - that book made me a fan of McDevitt's storytelling since and I've read and enjoyed all his books, except one - the disater one since I rarely like those - who knows about the new one. There is a lot of potential there too.
In Fantasy to come: Dark Volume by G. Dahlquist, Steel Remains by R. Morgan, possibly Dance with Dragons by GRRM, Lord Tophet by G. Frost, The Alchemy of Stone by E. Sedia, Principles of Angels by J. Fenn, The 10 Thousand by P. Kearney. Less competition here, but who knows there may be several more titles I am less aware of...