I don't know anyone who's managed to finish Underworld, but White Noise is pretty great. My top books of 2007 (no, I haven't read them all but I can't wait to):
The Best of LCD: The Art and Writing of WFMU, edited by Dave the Spazz
Taking Things Seriously: 75 Objects of Unexpected Significance, edited by Joshua Glenn and Carol Hayes
Reading Comics, by Douglas Wolk
The Shock Doctrine, Naomi Klein
The World Without Us, Alan Weisman
You Don't Love Me Yet, Jonathan Lethem
Novels in Three Lines, Felix Feneon (translated by Luc Sante)
Dream: Reimagining Progressive Politics in an Age of Fantasy, Stephen Duncombe
The Red Men, Matthew de Abaitua
What of The Night and Letters From Cuba, Maria Irene Fornes