I have a couple videos I really like.
For strength, Jackie Warner One-on-One is probably my favorite. This new one is good too, except the modifier issue and the speed of reps - the previous had neither of those problems. I really tend to like videos that just walk you through the sort of routine you'd do in a gym (doing a set of one exercise and moving to the next), rather than elaborate routines, so this works for me.
For cardio, I love me some Tae Bo. It's that same "here's a move, lets do it a few times" style, rather than elaborate dance sequences, and there's something kitschy about his little neon shorts.
The Biggest Loser Cardio Max video is also that style, and gets my heart rate up. My current favorite isn't a video at all, but a Wii game (Gold's Gym Cardio Workout)...one of the few game-based workouts that gives me the same heartrate and calorie burn as running on my treadmill, and as an extra bonus, does some good back/ab/shoulder toning. Plus it lets you punch to Eye of the Tiger, which makes you feel like Rocky!!