No one's mentioned the Shannara books yet?
One of the funny things about the Sword of Shannara vs. Thomas Covenant (the first trilogy) is that the First Trilogy of Thomas Covenant is more of a rip off of the Lord of the Rings than the Sword of Shannara. The First book in the Shannara series get's obvious cues from Lord of the Rings, but the first trilogy of Thomas Covenant is a blatant rip off.
The first book has it where you have the all powerful ring that the Dark lord wants and the group has to go on a quest through catacombs to find a solution to things...or so they hope, entirely with their Gandolf figure and the fellowship as well as the council.
In the second book you have the Ring bearer now on their separate journey in the mountains as well as the Battle of Helm's Deep.
The third book you have the siege of Gondor (well, it's not called that, but it's that in all but name), and the ring bearer taking the fight to the Dark Lord with his faithful companion.
The parallels are far more than that for one who looks at it, but I won't go and make a ten page comparison. Sword of Shannara is obviously based off Lord of the Rings and gets slack for it, but ironically the Thomas Covenant trilogy which also is very blatant on it never get's called out on it.
I like both series, I just find it ironic.
Elfstones of Shannara on the otherhand is awesome (still has a Helm's Deep moment though) and perhaps my favorite of all of them.