Depending on taste,
Charlie Stross (Singularity Sky, Iron Sunrise, Halting State, Accelerando, Glasshouse),
Ken Macleod (The Star Fraction, Execution Channel, The Night Session, Learning the World, The Engines of Light trilogy etc),
Alastair Reynolds (Century Rain, Revelation Space series),
Iain M Banks (Consider Phlebas, Player of Games, Against a Dark Background, Use of Weapons),
Michaal Marshall Smith (Spares, Only Forward),
Gary Gibson (Stealing Light).
All of them are very good, IMO, there are quite a lot of good British SF authors about as the mo (all of the above are Brits).
There are also the classic golden age authors, Heinlein (The Moon is a harsh mistress, Stranger in a strange land), Asimov ( the first 3 of the Foundation series, Robot series), Clarke, Philip K Dick, although the writing tends to be a bit variable.
David Brin's Uplift series is good as well, as is Greg Bear's Eon, Kim Stanley Robinson's Mars trilogy, Early JG Ballard, Neal Stephenson, William Gibson, Bruce Sterling etc etc.
I read an awful of SF (and anything else really 😉 )
Edit: forgot Jeff Noon, he is very good, odd Mancunian cyberpunk.
Joe Haldeman's sequels to Forever War are absolutely atrocious, btw, give them a miss