There are a few fantasy series that I like, but I am picky when it comes to fantasy. The whole series has to be good for me to own them.
Lord of the Rings, The Chronicles of Thomas Covenant, and The Sword of Truth are the fantasy series I own. If anyone knows of a fantasy series that are comparable to these, please let me know. Don't bother mentioning The Wheel of Time by Robert Jordan, as I tried to read it, got through four books, and gave up because I simply could not figure out why other people enjoy this series.
I definitely own a lot more sci-fi books than fantasy, some are a series, some are single books.