Kim Stanley Robinson's Mars trilogy, best SF there is IMO
And the second best would be Richard Morgan, anything with Takeshi Kovacs in.
And the last of the three would be Roger Zelazny with Lord of Light, which hides is scifiism well but is absolutely stunning (his Chronicles of Amber are worth a dip as well, not scifi at all, more intelligent modern fantasy, but the line between the two's pretty skinny anyway)
Robert Heinlein- the Moon is a Harsh Mistress
Ken MacLeod's Fall Revolution series
Iain M Banks's Culture novels, starting at the start when he was still good
Charlie Stross, I don't get at all, Ken made me get one of his- Singularity Sky? And it was pretty rotten. Not so much space opera as space panto.
Alastair Reynolds if you want your space opera cold and black. Not very good in a lot of ways but very good in others.
Peter F Hamilton- absolutely rotten, in parts, but he's pretty much the master of Blowing S**t Up In Space. Can't right characters or dialogue but he gets away with it, on account of the SPACE ZOMBIES and the big mad ideas and the absolutely stunning setpieces. Reality Dysfunction is the place to start, his later stuff manages to actually do the stuff he does badly even worse. (ironically, he could actually do characters and relationships in his earlier books)
John Brunner's Stand On Zanzibar maybe? Not very explodey but absolutely brilliant. I've not read that for years actually, I should. Or Michael Marshall Smith, starting with Spares.