Heinlein- the earlier and more juvenile stuff holds together the best, but all is worth reading.  I like later novels Friday (tight futurism) and Number of the Beast (more like Stranger).  Fave:  the admittedly milspec Troopers
William Gibson - Bridge, strand, Zero history, all of it.  read it.  
Richard K Morgan - Kovacs novels are farking fun adventure sf.  Prefect novels are ok as well.  He also did a fantasy book with a gay protagonist that showed some spark, can't remember the title, I can handle fantasy as long as it's not too much "Merlin intoned runes from the eldritch scrolls against the troll hordes in books 3, 5 and 9.  
Neal Stephenson - Cryptonomicon and System tril. are must read, the rest is ok.  liked Anathem.
Gaiman - inconsistent, liked the "Gods".  some ok shorts.
Piers, Anne McCaffery, Andre Norton, Asimov (fiction, haven't like his NF and astronomy books as well), I grew up reading their novels and Analog/Asimov's.  
Any PK Dick- come on, bladerunner, ya'll.   
Rudy rucker - robot books are worth reading and interesting
I want to check out GRR martin after watching game of thrones.  seems cool. 
Glad to see there's a good amount of SF guys here.