I second Ray Bradbury, Ursula LeGuin and Frank Herbert - The Martian Chronicles is a positively brilliant collection of soft science fiction short stories, and LeGuin's books - The Dispossessed or Left Hand of Darkness, to begin with - are remarkable, thought-provoking works. Dune, is to me, the greatest soft science fiction novel ever.
I loved Orson Scott Card's Enders Game and Speaker for the Dead.
I would also recommend Man in a High Castle by Philip K. Dick, which is a fascinating novel in which Japan and Germany won WWII, and Japan now occupies California. And although there are some frankly misogynistic elements to his work, A. E. Van Vogt is a criminally underrated soft science fiction author. I recommend the Silkie and his Null-A novels, particularly The World of Null-A.
Dan Simmons' first 2 Hyperion novels (Hyperion and The Fall of Hyperion) are ridiculously good soft science fiction - a retelling of the Canterbury tales set in the distant future.
In addition, because the technical jargon was pretty much made up at the time he wrote it (even though it now has a lot of currency), I consider Neuromancer by William Gibson to be outstanding soft science fiction.
Let me also recommend a few more obscure titles:
The terribly overlooked Elizabeth Hand novel Winterlong is another favorite soft science fiction book - it's a beautiful and eerie, goth-y post-apocalyptic novel set in Washington D.C. I also loved Rumors of Spring by Richard Grant - a sort of environmentalist future fairy tale.
I should also add that my wife is actually a much bigger science fiction fan than I am - she is particularly fond of Golden Age sci-fi, and recommends the Foundation series, Arthur C. Clark's Rama books and Kim Stanley Robinson's Mars series (which seems hard from the outside but is really more political and social commentary).
There's more that we're forgetting which I'll be kicking myself about later, but these are the ones that come to mind tonight.