Excel 2007 : Retrieving unique values from a list by INDEX,MATCH, COUNTIF

Column B3:B100 contains a list of postcode sectors, which appear more than once. I want to create a list in column C in which each unique postcode in column B appears only once. Previously I have sorted copied and pasted or used a pivot table but am trying to sort column C out with a formula. I have tried to use a INDEX, MATCH, COUNTIF formula (see sample) but it is not working! Am using in cell C4 ( leaving the first cell in the unique list empty) =INDEX($B$3:$B$100,MATCH(0,COUNTIF($C$3:C3,$B$3:$B$100),0)) but am returning #N/A. which should appear when the list of unique values has completed in Column C.
Could someone please help or offer an alternative formula.

Hi Fortis, my first attempt, thanks for your response and solution.
Mikey

Thanks for quick response and showing both solutions,
Rgds
Mikey