Add in Neal Asher for the 2000s. Breakneck action space opera, wily AIs, disgusting wildlife, rarely a dull moment, Banks on speed.
Also, almost any Vance is bound to be enjoyable, after you acquire the taste (the P.G.Wodehouse of SF, not that it is comic, more of a sardonic tone).
And yeah, Lem, The Cyberiad, the non-existing-book reviews, whatever. Also, Pierre Boulle, amazingly unknown in spite of the movies (Les Jeux de l'esprit should be mandatory reading in some sophomoric circles.)
I would highly recommend adding Richard K. Morgan's work to the 2000s. Very very well written stuff.
You will find the occasional oddity: a couple of Samuel R. Delany's early Ace Double publications just popped up, and Chip is still very much alive. Chip has been in the business a long time - if they've lapsed into the public domain, it's because he allowed them to.
(It is weird when you see stuff appearing on PG by people you know/knew - Delany among the living, and Terry Carr and Laurence M. Janifer among the deceased.)