I have seen this (I'm also using it):

$(document).ready(function(){
   // do jQuery
})

and also this (I have tried lately):

(function(){
   // do jQuery
})(jQuery)

both works fine.
My question is what is the difference of the two ( except on how it looks ).
Which one is more proper to use?.
Can you give me some pro's and con's for each?
Is there also another way of doing this?
(also help me with the title above. SO suggested, "The question you're asking appears subjective and is likely to be closed.")
Thanks everyone.