Yoga?

There are a good number of people here who do Yoga and agree with you that it really kicks your butt!  I couldn't offer you any suggestions whether it's better to do it before or after a strength workout though. I couldn't imagine doing a hard strength workout afterward though because a good Yoga session wipes me out.

Give Bikram Yoga a try some time.  It will REALLY waste you    

I agree that a hard strenth work out would suck after yoga, but I cant imagin yoga after a hard strength work out I will try it both ways and post my findings? Where do you do Bikram Yoga?

I try to do Bikram Yoga at LEAST 1x per week - usually early in the morning and then I do my normal evening workout (for me it is ST and a spin class) I have done it right after running and/or a ST workout, just depends how hard you push either one. I would definitely recommend doing it after a workout (if directly after) or at least give yourself a few hours to recharge/rehydrate before hitting the gym again. Plus you are so relaxed and calm at the end that I couldn't imagine having to refocus on another workout right away.
For me it is a great way to focus on core work,stretching and pushing myself in a different way. LOVE IT! Was going to Bikram classes 4-6x per week and felt great, but just finding the time to go is a challenge! Give it a try!
Bikram studio I go to: The Bikram Institute - Indian School and Miller Road
'Flow' Hot Yoga - Sumits Yoga Scottsdale - McCormick Pkwy and Hayden

The first is strict Bikram format while the other is more of a combo of Power Yoga/Bikram in a hot room - both AWESOME!
BTW - I also have a few good dvd's at home...Yoga for Athletes and Brian Kest Power Yoga...both good esp when you can't get to a studio. I want to get the DVD 'Flexible Warrior' as well.
Hope it works out for you!