@Frank Apisa,
I think that's one of those grammar rules that's really archaic. I heard a debate on it years ago and it was quite funny. The only time I ever consciously make the effort is if I have to write To Whom it May Concern; otherwise, no. It's too unwieldy.
From Scribb:
Where does the “rule” come from? The rule is generally attributed to the 17th-century writers Joshua Poole and John Dryden. They based their objection to preposition stranding on Latin grammar. In Latin, a sentence can never end with a preposition.
So... two guys thought this was a 'should'... who cares?