I love Davina's Super Body Workout dvd. There are two main sections - Super Fit and Super Sculpt. Super Fit is a kickboxing/aerobic type workout (it's pretty tough for me, but I am a smoker!), and Super Sculpt is a strength workout that incorporates cardio intervals. I love doing the Super Sculpt because I get cardio and strength training all at once. It's a flexible workout - it can be easy enough for a beginner, but challenging enough for the more advanced, so you can add more weight, etc., as you build up strength. You basically do squats and lunges while lifting weights, then do a 5 minute cardio interval, then do another set of squats and lifts. The music is pretty good, too! Also, there are extra workouts on there for abs, legs, and upper body so you can add one of those onto the end of the regular workout if you feel like doing a bit more. I think it's a great dvd and I have used it for months and months without really getting tired of it. The only equipment you need for it is a set of handweights (I got a fitbell set on Amazon for about £15, I think, for three different sets of weights.)
For something mellow, I like Dolphina's belly dance dvds. They are fun and do tone you up, but without making you all sweaty and gross.