well alton towers is quite bad cuz the queues are wayyy too long unless u purcharse a "Priority" ticket... which is like ?65... so it depends if u think its worth it...
The rides are the best i think... i reccomend "Oblivion" and "Nemesis" - all the one's with the big queues lol..
But the best theme park IMO in England is "American Adventure" in Derby... fantastic rides... but be careful of the hot dogs... i choked on one last time i went... the whole damn sausage went down my throat and burnt it and i choked... and i couldn't talk for a week hehe...
Have fun !
- Mist