I started reading Bronson but got bored of it, wasn't intereting enough to keep my attention. Might try again another day as the guys a nutter.
Chopper was good but drifted off towards the end. Its about his life of crime as apposed to prison life but I'd still recommend it. Prefer the film. I read Chopper 2 as well but left it there, I think he's wrote about 10 or 11 books now. If I remember correctly, he'll mention someones name, write stories about them then move onto the next person, almost like being sat in the pub with him telling you stories.
I've got another book yet to read called Screwed by Ronnie Thompson, its about life as a prison guard. His next book is Banged Up, supposed to be very good apparently.
They aren't prison books but I'd recommend these two also.
The Guv'nor by Lenny McLean, an old-school bare-knuckle fighter.
Watch My Back by Geoff Thompson, he was bouncer for some of britains roughest pubs.