Between the two, I vote for LASTICS (regular workout and then the advanced workout). I found that Lastics really helps with actual flexibility and did make a difference in my workouts and help with the fact I sit at a computer 10 hours a day. It is long, but I don't find it boring or too long. In fact, there are three exercises I wish she held a bit longer, so instead I take those three exercises and do them myself throughout the day. The instructor has pointers at the beginning of the video, which I listen to about once a month to reinforce form (the poster above noted the instructor has good pointers, and I totally agree.) I know the workout is broken up into sections (not sure if they are chaptered), but I do the entire workout at once for a full body stretch.
Note that my guy, who doesn't even have the flexibility of a steel pole, did Lastics with me every day for about 2 months and he hated/loved it. He would shake, sweat, be very uncomfortable and curse...but then he started noticing he had a bit of range. He stopped doing it, not sure why, but once in awhile brings up that he needs to start stretching again. When he did it with me, he noticed that his hamstrings and quads were much looser and didn't hurt after work or waking up.
I would also recommend Gravity Yoga (Lucas Rockwood). Each 15-20 minute video has about 3-4 moves and you hold each move for 3-5 minutes. This is the kind of stretch that helps my body. I personally do not like Yoga/pilates moves - I like deep stretches that hold for a long time. I subscribe to FMTV.com and that is where I found Gravity Yoga and Sandra Doubell (also recommended).