Mine is a 10 Minute Solutions one - 'Blast Off Belly Fat'. Nothing has ever made any difference to my gut, even when I was running 3 times a week I didn't feel like I lost an inch, but this is wonderful. It's tough and there's still some exercises I really struggle with but I have really seen results. My abs have got stronger and more toned. I love it.
For pregnancy definitely Tara Lees yoga... probably completely the opposite of your choice - very gentle and relaxing!! Loved it all the way through, even when I was only fit for the supremely easy 'and sit and breathe' section!!