Now, I loved the Wasp Factory. It was the first of his novels I read, and I was carried away by the narrator's world and obsessions and isolation. It did seem to be a punk novel.
I've read most of Iain Banks' "normal" fiction novels, and I know what you mean by feeling a bit confused at the end. I enjoyed the ending of Walking on Glass and how the three stories complemented one another, but it was immensely frustrating at the same time. I'll have to re-read Canal Dreams to try to work out what was going on there.
The Crow Road is his most satisfying novel. The TV adaptation was excellent, as well. I've got the DVD of that somewhere at my sister's house