I'm going to go ahead and join the "Tolkien is way too long-winded, but his books are still enjoyable" club. I actually read the Hobbit, Lord of the Rings trilogy, Silmarllion, and The Children Of Hurin, and enjoyed them all.
I'm going to second the Discworld novels; I only read the first one thus far, but it was immensely enjoyable and the rest are supposed to be good, too.
The Hitchhiker's Guide To The Galaxy is a great series. The last book is a bit of a downer ending, but I see it as him saying, "Fuck this, I'm done," which I would be too after writing four completely nonsensical books about the same character.
Now, for my own advice...
You should definitely check out some of Raymond E. Feist's stuff if you're into fantasy. I really like his writing style, and his characters are great. Start with the two Magician books, Apprentice and Master.
Another book I read, which may not fit with the rest of this thread as it isn't Sci-Fi or Fantasy, is City of Thieves. It's a great book. Really well written and such. It's a historical novel set in Russia during WWII. My step-father suggested it to me, and it's really an amazing book.