Any of Terry Pratchett's "Discworld" series- two or three times over!! I read them as they came out, then later I read them in order of main characters- I'm just working through my "Rincewind" set again!!
Any of Stephen King except the Dark Tower series- think that is actually plagiarism on Michael Moorcock and I find the language boring, as did I Tolkein, who, along with JK Rowling I think i are the most over rated authors of our time!! (I read the Ring trilogy three times at Art School as I could not work out what the fuss was about- still can't, found the film well made and SO boring!!
Any of Dean Koontz- I like his "proper" endings- no loose ends, or only a few, anyway!! I do wish he would do his research properly, though, the mistakes he makes are glaring.
Worked my way through the Jean Aeul books- I found the first one fascinating but then she lost the plot a bit and turned to amateur pornography, but I just skip pages when I come to that. The descriptions of the landscape is wonderful. Again I do wish she would get not just her facts (Wolves do NOT sweat!!) right, but also her colour genetics!! I hope no-one actually thinks these books are factual, or even based on fact- I'm looking forward to Ayla inventing the wheel and the microwave oven in the next book- I shall see it through to the end, though. The writing style is now totally out of it's depth but the theme is gripping!
Phillipa Gregory- I read "The Other Boleyn Girl" and I was hooked! I haven't read historical novels for years but these are fascinating, especially so as I was born and brought up in the area she is describing, but 500 years later- so I know, personally, all the major landmarks she describes.
I read maybe a book a week so I need a few to keep me busy