You can use BVH animations with your model(.X or .FBX).

To use BVH animations with your model:
 Model model = content.Load<Model>("bear");
 AnimationController c=new AnimationController(game, model, 0);
 ModelAnimationCollection a = content.Load<ModelAnimationCollection>("bear_walk");
 c.Animations.Add(a[0].Name, a[0]);

There is a collection of free BVH files at

http://www.bvhfiles.com/