There are a couple of older series that I like.
The first is David Eddings Belgariad and Malloreon series (each are five books long). These are of the "peasant finds out he is actually a key part of saving the world" genre but I found them very entertaining, with fun character interaction. The problem with Eddings, though, is that everything he has done since has basically recycled these characters into different plots, even down to the same banter between characters. The Sparhawk series is okay but derivative.
Another is Barbara Hambly's Darwath books or the Winterlands series. Actually, I enjoyed all of her fantasy novels that I have read (she also writes historical fiction and mysteries).
David Duncan has written several series that I have really enjoyed. The Seventh Sword is about a dying young man (in our time) who finds himself transported to a different world in the body of a master swordsman.
The Pandemia books are good too. I didn't really care for his King's Blades books, though.