At the risk of sounding serious for a change...
On the matter of self adhesive book covers, I'd say stay away from them. Personally, I use the types that are clear plastic, with only an upper and lower adhesive strip that adheres to the inside cover. The book can then have enough freedom inside this envelope to "breathe" without losing any artwork through chemical deterioration, or rubbing.
I know brand names are different across the world, but (digging through my waste bin) I've found the ones I use are called FILFAX School book covers. Follow the instructions carefully, as they can be a bit crafty to put together the first couple of times.