Strength is important. Even Morehei Ueshiba, the founder of Aikido, was physically strong in his younger days.
One can have functional strength, without having a body-builder's built. I'm not a fan of weight machines myself. I prefer free weights (barbells, dumbells, kettlebells and possibly clubbells. I find that Kettlebell is good for functional strength. But's it's not for wimps http://www.dragondoor.com/b15.html
I haven't tried Clubbells yet, but there's good testimonials, including from Kettlebell enthusiasts. I've been pleased with Coach Sonnon's material so far. I don't think it's available for people outside US. So I'll have to wait.
http://www.clubbell.tv/clubbell.html
