Ok, my feelings about Clarke are that he writes slightly rubbish stories with weak characters and great ideas. I'm not sure who the modern equivalent of that is.
From the other recommendations in here, I'd give my unreserved backing to Iain M. Banks and Alastair Reynolds, both space opera with some nice big leaps of imagination, and my reserved backing to Peter F. Hamilton (who entertains and infuriates me about equally), Dan Simmons (Hyperion is great, but he's reportedly gone off the rails), Neal Stephenson (later works too long, struggles with endings) and Stephen Baxter (some of his are a bit dull - he's maybe closest to Clarke, though.)
Corey, Stross, Sawyer and Scalzi I don't particularly rate, based on what I've read so far. The others I haven't read enough of to form an opinion, except maybe Weber who writes entertaining, undemanding military SF.
A couple more: Kim Stanley Robinson has a major new book out this year (which I haven't read) and Ian McDonald probably hasn't written a bad book.