The Biggest Loser: I have the Cardio Max DVD from the Biggest Loser workout DVD collection. I have to say that this is a great choice for beginners. The workouts are shorter, and it has the option of six workouts that are arranged for a 6 week program. It is also has options for people who are at the beginner and more advanced levels. They even give suggestions on how to modify the workout for people with a somewhat limited range of mobility. (PS I am pumped that The Biggest Loser has just started a new season!)
Windsor Pilates: The Windsor Pilates Buns and Thighs DVD may seem simple at first glance, but you will definitely feel the burn! The moves are very basic, and super quick and easy, but believe me, it will give you what you are looking for with this workout. It is definitely one that needs to be done consistently for a longer period of time to really be able to see the results and not just to feel them during the workout though. I do this one year round.
Tracy Anderson Method: I recently added two Tracy Anderson Method videos to my collection, and let me tell you, her method DVD's are for more advanced fitness levels. They are also not the pop it in and go type of workouts because they have complicated moves that have to be learned before you can really get into the workout. I know that they will be a pretty good cardio workout once I learn them, but they are going to take quite a bit of time to master. All in all, they aren't at the top of my list for home workouts.
If you haven't checked out my post on the importance of yoga, then I seriously encourage you to do so now. I also do yoga at home, and I find it especially important after stressful weeks and long runs. I also got my yoga DVD for a great price at Walmart. I have found that Walmart tends to have a great workout DVD selection, especially in January.
If you don't want to take your chances in the sporting good section at Walmart, then you can check out collagevideo.com to get your DVD's. This website will let you return DVD's if you try something and decide it's not for you. I have never personally used this website, but I heard about it in a review on youtube, which is where I normally go for reviews before I buy a workout DVD.