I need some suggestions for a good sci-fi series. Any idea?

Isaac Asimov's Foundation and Frank Herbert's Dune are the first that come to my mind.

If you are interested in something that's funny (British style), then get The Hitchhiker's Guide to the Galaxy by Douglas Adams. Not "true" science fiction, but hilarious. And if you can find a recording of the original BBC radio series, it's even better. (The TV show sucked, though.)

Lois McMaster Bujold's series around Miles Vorkosigan.

Greg Bear's Forge of God and Anvil of Stars.

David Brin's Uplift series; and Earth was really good too though only a single novel.

Anne McCaffrey's Pern series (though some argue it's Fantasy and not SF)

I'm sure there are more I'm not thinking of right now...

Let's see (not repeating the previous suggestions although cautioning you that Dune was great but the series fell off after the second book in a big way):

Larry Niven wrote an entire future history with some good hard science in it (if that's your cup of tea). I can't possibly list them all here, but you can always try Ringworld or the Mote in God's Eye as a starter.

Arthur C. Clarke, Childhood's End (It's not a series, but it is a great book)

Frederick Pohl, The Heechee series (Gateway, Beyond the Blue Event Horizon, Heechee Rendezvous, The Chronicles of the Heechee)

Orson Scott Card - Ender's Game, Speaker for the Dead, Xenocide, Children of the Mind, etc.)

Jack Chalker - The Well of Souls books - Midnight at the Well of Souls, Exiles at the Well of Souls, Quest for the Well of Souls, The Return of Nathan Brazil, Twilight at the Well of Souls. Chalker has written of ton of books, most good, but these are probably his best.

Phillip K. Dick - He's an original creepy SF author (wrote the book that they based Bladerunner on, same for Total Recall). The Three Stigmata of Palmer Eldritch, Do Androids Dream of Electric Sheep (i.e., Bladerunner), Radio Free Albemuth.

F. Paul Wilson has written many books, some SF, some more like Fantasy, and some that are Horror stories. He's got a keen mind (he's a medical doctor and author) and his books can captivate you immediately. A lot of his stuff is out of print, but, if you can find it, I recommend Healer.

Piers Anthony wrote a couple of nice sci-fi books, but he has a penchant for going on too long in a series long after the idea has lost its oomph.

ya pier anthony's adept series is a mix of science and magic, its pretty good

I want to mention too that Frank Herbert did not write only Dune he has written other books as well and equally good. A couple of them is the Godmakers (very nice book) and Starship Troopers (yeah the book that the movie came from, but with no comparison the movie sucked while the book was fantastic). Enjoy Aik :cool:

What? Robert Heinlein wrote Starship Troopers.

Yes, Robert A. Heinlein wrote Starship Troopers!

God Bless the Rodger Young!

I happened to like Steven Donaldson's Gap Series a lot.

The first one is strange, the next four are excellent. In my opinion....

What? Robert Heinlein wrote Starship Troopers. Did he? Ok i haven't read for about 3 years so i most possibly am wrong. :doh:

Don't like to repeat previous posts, but I feel Dune deserves the honour. :thumb:
Personally I enjoyed the first three books.
I also can suggest Dan Simmons' Hyperion series. Especially the first book is mind-blowing.

if you like military-like sci-fi then dreamland isnt bad(cant remember author) its a really good book.I would HIGHLY reccomend dean koontz watchers, the book is mind-blowing

Well I think Foundation is a little bit too over-science-focused. The way that everything is atomic. And it pushes the idea of matematic "divining" of the future too far (imho).

I like the Dune more. I will never forget the insight in the Judas's motives God emeror of Dune gave me.

If you don't mind cyberpunk, then go for Neuromancer, Count Zero and Mona Lisa Overdrive by Wiliam Gibson. His style is sometimes quite hard to comprehend (but I've read it in Czech, and the quality of the translations varies), but I like it a lot.

Well, I'm after the Dune series so far.

Just a thought, I'm more into hard sci-fi than soft. Things with some basis int he real world are more interesting IMHO.
Methinks I'll also go find Neuromancer, I've heard some good things about that.

If you're in to hard SF, then two of the authors I gave you fit the bill.

Here are a few hard SF authors I know:
Greg Bear
David Brin
Poul Anderson
Frederik Pohl
Gregory Benford
Kim Stanley Robinson
Arthur C. Clarke
Vernor Vinge
Robert L. Forward
Jack McDevitt
Charles Sheffield
Larry Niven

H.G. Wells - everything... Simply everything... :) Well, not just everything, but "the Invinsible Man", "The Island of Dr Moreau", "the War of the Worlds", "Time Machine", "the Food of the Gods"... These five are masterprise in the Science Fiction.

David Drake's "Hammers Slammers" is a sweet series of military SF. Some of the stories just give you the chills -- they're all based on his own experiences in Vietnam, but set in the future on an interplanetary scale.

Well, H.G. Wells had found out nearly all topics of sci-fi, and it was only the end of 19th century. Hehe.
Except computers, of course.

Edit: And androids, robots and so. (R.U.R. - a drama about robots by Karel Capek (Czech!), 1930s)