Some of the Shannara books are decent. The First King of Shannara and then Sword of Shannara were mostly enjoyable. I'd skip the latter two of the original trilogy. Heritage of Shannara was ok, nothing stellar but solid so it might be worth a read. Not sure how the newer books are. I liked the Word/Void series although its set in the modern world and is quite a bit different to the others.
Sword of Truth isn't worth it. Halfway in it gets so pretentious with the heavy-handed analogy to communism, and the later books are downright painful to read most of the time as he keeps explaining the same crap over and over and over and in very annoying manners (he'll spend an entire page drumming up how intelligent a character is to turn around and have them ask stupid questions and sound like a 4 year old on the next page, so that he can then have one of the other characters explain it in a long drawn out manner). I never got as annoyed as with Wheel of Time, but I grew tired of the characters which was the only thing that kept me reading after about book 4, but he seemed to be trying to make you not like his series by the end.
Redwall is good, but I'm not sure how well it holds up for older adults. Its worth a try and the books are pretty quick reads. I'd recommend starting out with Mossflower and then maybe Martin The Warrior followed by Redwall itself and then follow the series from there.
I really liked His Dark Materials, but its not really comparable to any of these, and the third book really changes the tone of the series so you may or may not enjoy it. The first two books are probably my favorite fantasy/somewhat sci-fi books that I've read.