I think I like workout DVDs so much because I love workout classes at the gym. However certain classes are only at certain times which don't always work in your schedule, plus the good classes are always really crowded or cost extra money. Owning a workout DVD collection is like having your own personal selection of workout classes/a personal trainer at home.
Here is a little bit about my favorites -
Insanity - this Beachbody 60 day workout routine will be one of the hardest things you ever do, which is why I love it so much. I have never done so many pushups in my life and it definitely reminds me of volleyball offseason training. I highly recommend getting a workout partner to do this one with you. It is will make it a lot more enjoyable plus you are more likely to stick with it. My husband and I tackled this as our first workout adventure as a couple and it was awesome. We both got great results and definitely tried to make it fun with silly faces and jokes. These DVDs are also great workouts to mix in your normal workout routine as they have so much variety and cross training. You need a little space, but no equipment!
Winsor Pilates - I bought 2 Pilates DVDs once at Target and got lucky that I stumbled upon Winsor Pilates. Mari is known in LA for training many celebrities and she definitely knows her stuff. Most of her DVDs are short, but are the best ab workout you have ever gotten. I have had my Pilates DVDs for over 6 years and I still use them. I have tried out other pilates trainers' DVDs, but I don't like any of them as much as Winsor. Looks like she has a lot of new stuff out now too.
My husband and I are on our third week of P90X. If you ever are watching late night/early morning TV you may be tempted to purchase this as it is always on infomercials. I think it lives up to the hype. You do have to have some hand weights, resistance bands and/or pull up bar to be able to do the workouts. The pull up bar is awesome and just wedges in the door frame so you don't have to use screws or anything. I am working on doing chair-free pull ups right now. I love these workouts because they target different muscle groups on each day. These workouts do last from 1 hour to 1 1/2 hours so you have to have the time to devote to getting them done. The 90 minute yoga video is killer. My favorite part is that Tony (the trainer) is really quirky and he makes it very entertaining (I just found out yesterday that he is a former comedian so now it makes sense!)
I think Beachbody puts out the best workout DVDs. They are expensive, but they are tools that you will have for a long time.
I hope this helps if you are in the market for a new workout routine. Have you tried any of these? Are there other ones that are your favorite?