I suggest reading widely within the genre; you're not going to know your likes & dislikes until you're tried a few things.
There are some excellent resources on the web. For example the
NESFA Hugo recommended readling list has a bunch of stuff, both SF & Fantasy, short stories and novels that are worthwhile.
A good way of sampling a range of writers is to read a few short story anthologies.
Gardner Dozois edits an excellent year's best collection as does
David G. Hartwell. They are excellent samplers, you'll get a taste of different writing styles and writers.
Below are books I'd recommend to the sci-fi newb. Many of them are classics of the genre but I think they should be read because they are all relatively easy to get into, you don't need to be familiar with genre conventions, they cover a range of different sorts of SF and they are all good reads. Some are the first book of a series but they can all be read as stand-alones.
SNOWCRASH by Neal Stephenson.
It's a rollicking rollercoaster of a ride. This was his 'breakout' book. It's fast paced, entertaining, and has enough neat concepts to fill ten books.
The MILES VORKOSIGAN books by Lois McMaster Bujold.
Start with "THE WARRIOR's APPRENTICE" or you could get the omnibus volume "YOUNG MILES" which contains "THE WARRIOR's APPRENTICE" and two other stories.
DUNE by Frank Herbert
This one's a classic. It's the first of a series but can be read as a stand-alone. Not to be confused with the prequel books written by his son Brian Herbert and Kevin J. Anderson.
PLAYER OF GAMES by Iain M. Banks.
I'm putting this one with a caveat. I didn't like his writing the first time I tried reading him; I was probably too young at the time. Now, I think he's one of the best writers around.
RINGWORLD by Larry Niven.
Another classic. Also the first of a series.
THE HITCHHIKER's GUIDE TO THE GALAXY by Douglas Adams.
This is more lighthearted and humourous. Also the first of a series.
NEUROMANCER by William Gibson.
Computers, hacking and gritty near-future scenarios. This cyberpunk classic caused a huge buzz when it was released. "NEUROMANCER" and the two sequels, "COUNT ZERO" and "MONA LISA OVERDRIVE" comprise the SPRAWL trilogy.
THE MOON IS A HARSH MISTRESS by Robert A. Heinlein.
Yet another classic. This is from Heinlein's earlier period. As he got older, his writing got, er, eccentric.
The FOUNDATION trilogy by Issac Asimov.
Yet another classic. The trilogy comprises: "FOUNDATION", "FOUNDATION & EMPIRE" and "SECOND FOUNDATION".
THE SPEED OF DARK by Elizabeth Moon.
This is a more recent publication. The main character is autistic and the story is told from his point of view.
By the time you've got through these, you should have a much better idea of your likes and dislikes.
