I found yoga very useful while I did it, but sadly it's hard for me to find the time these days.
Of all the types I tried, I preferred Ashtanga - there, the emphasis is more on the movement and trying - if you can't manage a certain posture, then compromise: it doesn't matter so long as you tried! I also found that as there was more movement, my muscles were "hotter" and it was easier to attain postures. More sedate forms of yoga (like hatha) didn't allow me enough of a warm-up, and I invariably put my back out with the "cold" bends.
This is the position that I find most comfortable.
Seated Forward Bend | Seated Forward Bends | Seated Yoga Poses | Asanas: Yoga Postures
Even after a year's practise, I could never get my forward bends as good as that! My favourite pose is the inverted lotus (a shoulder stand with the legs in lotus position) but I can't find a picture. It's towards the end of the sequence, when you're tired, and when you get the balance just right, it's great - you could stay there for hours!
I'd like to find a yoga class (preferably Ashtanga) near me, but there doesn't seem to be any helpful directory online - searching for "Yoga Classes, Leatherhead" will bring up classes in Central London (too far) but not the ones I suspect are available in Dorking, Epsom or Chessington (just about doable).