- Year Zero by Jeff Long (got about midway through it, but the plot kind of petered out so I lost interest. I will say that I loved The Descent though)
- The Wishsong of Shannara by Terry Brooks (can't remember why I didn't finish it)
- Elixir by Gary Braver (kind of boring)
- Northshore (Volume 1 of The Awakeners) by Sheri S. Tepper (I actually enjoyed this from what I remember, but I think other more interesting books came along)
- The Eternity Artifact by L.E. Modesitt, Jr. (good plot? no. sympathetic characters? nu-huh. keep reading? nope.)
- The Heat Seekers by Katherine Ramsland (hated the writing style of it after three chapters)
I'm sure there are more than this though. I'll have to look later on.
Let me know about any books you started, but never finished! I'm curious as to why!