Thanks for your suggestions guys - I'm going to have a look and listen through and get some learning done now!
On the whole slow vs. fast rhythm playing, I find it hard to play tight both slowly and quickly, although errors are less pronounced in faster passages (as obviously there is less room to go wrong in, unless you hit the wrong note).
I didn't have metal playing in mind as a rhythm instructor, and I'm not much of a metaller, but a lot of you seem to think it's the way forward for polishing the chops so I'll have a go!