I don't know how you're using these max values - you should have posted your script.
Anyway, a good way to jump is to set the Y velocity directly - like this:

var jumpSpeed: float = 8.0;

function Update(){
  ...
  if (Input.GetButtonDown("Jump")){
    rigidbody.velocity.y = jumpSpeed;
  }
}

This code has a problem: you can jump even while in the middle of another jump. To avoid this, you can set a flag when starting a jump, and reset it when landing on the ground - but the ground or other objects where the rigidbody can land must have the same tag - Ground, for instance:

var jumpSpeed: float = 8.0;
private var jumping = false; // flag jumping

function Update(){
  ...
  if (!jumping && Input.GetButtonDown("Jump")){
    rigidbody.velocity.y = jumpSpeed;
    jumping = true;
  }
}

function OnCollisionEnter(col: Collision){
  if (col.gameObject.tag == "Ground"){
    jumping = false; // reset the flag when landing on some Ground object
  }
}

need the script, not quite sure what you mean.. If you're using a character controller, you can use something like this:

http://unity3d.com/support/documentation/ScriptReference/CharacterController.Move.html

similar to above, one note: uses controller.isGrounded to automatically check for being grounded

not sure if your issue is one of move speed, or rotation. post the script if you could