Cinimod, I agree with you on the Nordic Ham Curls. Most injuries occur during the eccentric phase so these are great for both pre and re-hab.
An additional exercise which i’ve found to be useful in both pre and re-hab is (and i echo Cinimod’s comments about me not being a physio here) is stiff leg deadlifts, sometimes called romanian deadlifts.
http://www.youtube.com/watch?v=PnBREGM7pE0&feature=related
the strong eccentric element is important for injury prevention and they encourage strength through a full range of motion, another key area in preventing injury.
the progression from this is a single leg dumbell romanian deadlift.
http://www.youtube.com/watch?v=7eACTTzeh-E&feature=related
this arguably is a better choice as the unilateral element of the exercise has a higher cross-over to sport and the rotational portion of the movement (i.e. dumbell in right hand lowered towards left foot) places more emphasis on the bicep femoris which is, as i understand it, the most commonly injured of the three hamstring muscles.
hopefully you find this helpful!
cheers,
tom