Kebab said:
Thorpe is the best if you're looking for thrills nearest to "US" standards.
While I do think Thorpe should be visited by a ride enthusiast, I can only ever see that sentence being used by somebody who has never visited the States.
In fact, before I went to the States, if I'd thought that, I'd have never left the UK because it wouldn't have been worth the effort.
The advice is generally good though, those three parks pretty much cover most of the best the UK has to offer and are all easy to get to.
On top of that, I'd say The Ultimate is worth heading to Lightwater Valley for. I don't like it personally, but it's a hell of an experience anyway.
Then I'd also make the trip to Oakwood for Megafobia and the tea tray ride.
Flamingoland is worth checking out if you're in the area, but there's nothing massively special there - but some people seem to love it.
In terms of flats, Drayton Manor has my two favourites - Maelstrom and Pandemonium. It also has the highly rated Apocalypse. I love Shockwave as well, it's short and doesn't do much, but the zero-g <3. Plus it's the only Stand Up roller coaster in Europe still
That about covers it really, but I would also say that Fantasy Island is worth heading over to for Jubilee Odyssey. I loved it when I first rode it, but I'll give it a new review in September when I'll hopefully get to ride it again.