Neal Stephenson would be a good one.
Kim Stanley Robinson - his Mars series is particularly relevant today.
John Scalzi would be screamingly hilarious. Maybe he can lead everyone in a sing-along of "Redshirts."
Max, actually I am quite surprised at easily distracted you are, but we don't need to get into it here. I do rather like the idea of hunting down our science fiction in his or her lair though. My vote - FWIW - is WIlliam Gibson. I met him and Bruce Sterling at a book signing at MIT several years ago and he's cool. Actually they both are.
Hi Rich -- I used to exchange emails with Jerry way-back-when (circa the late 1990s) although I'm sure he won't remember me now.
In fact I have a framed photo on my office wall that was given to me by Jerry's son, Alex
My favorite sci-fi book ever remains John Wyndhams's Day of the Triffids. the BBC did do a series on it back in the 80's, but it was thoroughly rubbish and the "special effects" were super lame. I wish someone would remake that one properly.
As for traveling through time... my favorite episode of star trek was the "Stone knives and bear skins" episode (Star Trek Classic episode The City on the Edge of Forever)- that has some good ideas about what would be useful and what wouldn't!
And, in terms of Zombies, I really liked I am legend, though it ended a bit weakly in the movie