I'm going with P90x because it seems like a good balanced workout for getting more flexible and in better shape. I'm also working out at a gym for strength training. How's crossfit for flexibility and endurance??
Home training programs like P90x usually do more harm than good, especially in the long run!
Professional supervision of a qualified trainer is absolutely necessary.
I do understand that this can be very expensive for students, however I'm more than happy to help you and save you some bucks in the process.
Home training programs usually have a stong appeal, because they suggest that you can do it on you own, what is very convinient for students on budget.
The flexibility part in the P90x program is ineffective just by itself. I do not recommend conventional stretching to my clients at all.
However a well balanced personalized training program with lot of active flexibility drills combined with myofascial release and trigger point therapy, usually do the trick and make you loose.
Movement screening and corrections should be an essential part of any training program, without that you're basically just hurting yourself, and learning bad and dangerous movement patterns.
Before you do anything READ this
book.
If your goal is to be flexible and have a great endurance, than crossfit will be perfect for that, but I'd rather recommend kettlebell training.
Also make sure to find a qualified
instuctor.