Get some Hoya Pro-1 DMC's from Hong Kong, may as well get the best at a cheap price, reduce the risk of flaring and IQ loss etc..
UV Filters - Reduces Blue Haze caused by excessive UV light.
Circular Polarizing Filter - Deepens intensity of blue skies and reduces/eliminates none metallic refelctions.
Neutral Density Filters - Recude the amount of light entering the camera without affecting the colour balance. Normally used to achieve Longer exposures in daylight.
InfraRed (IR) Filter - Blocks light in the visible spectrum to to allow only light in the InfraRed spectrum to enter the camera. This produces images with a unique tonality and detail but requires longer exposures.