This is difficult to say without knowing your limiters and strengths. If you have difficulty generating force but are quite flexible and have a strong core, then weights wins out hands down. Most people aren't in that boat however. Personally, I'd lean towards yoga. I'm entirely too lazy to try and re-list all the great points listed by others, but the 2 main reasons I started doing yoga was to improve my flexibility and core strength. There are a great many other benefits to be gained through yoga, but those two are the key points that initially attracted me as a triathlete.
With regards to resources, I've heard excellent things about "
Power Yoga With Eoin Finn". I've never seen the video myself, but have the wonderful advantage of actually having him as my yoga teacher. He's awesome, and I would imagine that any video made by him is truly excellent. Check it out at:
http://www.vancouveryoga.com/videophotos.html Another video I've heard really good things about is John Scott's "
Primary Series". John is a UK based Ashtanga teacher, and from the description on his website, the DVD sounds amazing. You can check it out at
http://www.johnscottashtanga.co.uk/
<If you're gonna be dumb, you gotta be tough>
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