The Hollywood Trainer Cardio Sculpt, with Jeanette Jenkins.
The workout runs about 45-minutes, and it includes cardio segments plus toning with handheld weights. It's an extremely thorough workout that hits pretty much every major muscle area, upper and lower body. The pace is steady -- you won't get bored -- but not too fast or overwhelming.
I never know whether to call a workout "tough" or not, as it depends entirely on your fitness level. I have a feeling I experience more "tough" workouts than your average exerciser, given that my own fitness level is, er, a work in progress, with plenty of room for improvement. But for me, this is a fairly challenging workout. The first time I tried it, by the end I collapsed on the floor in a heap and did not get up for five days. More recently, I can finish without collapse, but it's definitely not a workout I can just go through the motions with.
More reviews are available here and here (as you can see, some folks love the DVD; others are not as impressed; but this tends to be the case with all things...) and Jeanette Jenkins' site is here.