See my reply to Corion above. I'm not against what "my" stands for. Just reserve its use for cases where it really makes a difference, ie. same variable name and type ($@% etc.) used in different scopes. Forget it for anything else.
That doesn't address what I said at all. If declaring variables isn't always required, typos in variable names can't be found. This would be a major loss. As such, declaring variables is always required, always makes a difference.