The Dresden Files by Jim Butcher
I can't say enough about this series. Probably one of the best series I've ever read. He has written 12 novels in it so far and has plans for 8-10 more and then an apocalyptic trilogy to bring things to a close. Writes about a novel a year with a short story or two in between so should hold your interest for a while if you wind up liking him. Really hope he doesn't die before he finishes things.
If you like Butcher, you might look at some of Simon R Green's books too, particularly the Nightside series and the Secret Histories series.
The Hyperion Cantos by Dan Simmons. I haven't read Ilium and Olympos yet but I hear they are very good too.
The Heir to Empire trilogy by Timothy Zahn is pretty good even if you aren't into Star Wars.
Some of the books in the Horus Heresy (Warhammer 40K) are pretty good but you do have to wade through some shitty writing if you want to read the entire series. Also, the oft-mentioned Eisenhorn and Ravenor novels are good reads.
Alan Dean Foster's work, particularly his Pip and Flinx books, is good.
Forever War by Joe Haldeman.
Armor by John Steakley.
Permutation City by Greg Egan.
Starship Troopers by Robert Heinlein.
Philip K Dick has written a bunch of good stuff which Hollywood has usually destroyed.
Frederick Pohl's Heechee series.
Debatable Space by Philip Palmer is kind of hit or miss from my experience. I like it but know people that absolutely detest it.
Grey by Jon Armstrong seems to have a similar response.
The Webmage series by Kelly McCullough.
The Silmarillion by Tolkien. If you enjoyed LOTR, you should definitely read this. The Children of Hurin too.
The Skyway series by John DeChancie.
Michael Crichton, anything before 2000 is solid. After that it is hit or miss.
Douglas Adams, pretty much anything he wrote. More humor than scifi/fantasy though.
The Shannara and The Word & Void series by Terry Brooks. The earlier books in Shannara are better but there is a 'neat' surprise later in the series.
Piers Anthony has some interesting stuff out their but it isn't for everyone. The Apprentice Adept series starts out good but gets pretty fuckin weird in the later books. The Incarnations of Immortality series is probably his best. Dead Like Me was based on the first book in that series. The Bio of a Space Tyrant series is also good but as with most of his work, tends to fall off towards the end. Xanth is good up until about book 12 or so and then it just gets old. He also wrote a series with Robert Margroff called The Adventures of Kelvin of Rud which is pretty good. He has some standalone stuff which is pretty good too. Off the top of my head: Chthon, Hard Sell, Triple Detente, Firefly.
If you are into mech type stuff, you may like some of the fiction written in the BattleTech universe. The Blood of Kerensky series by Michael Stackpole is good example. The Saga of the Grey Death Legion, The Warrior Trilogy and The Jade Phoenix Trilogy are worth checking out. One shot novels published prior to '93 were mostly good and after that things go downhill, with the exception of a few authors.
A lot of the Forgotten Realm's fiction is good too but I have those books in storage and haven't read them for years outside of some of Salvatore's work. Sounds like you probably are familiar with what's good there already anyway.