I am in need of a polarizer for my FX-1. I have found 3 options with the Tiffen brand:

72mm Circular
72mm Circular Wide angle
72mm Linear Warm

The guy at B&H told me to go with the 72mm Circular, but he really didn't know much about the differences. Any reccomendations?

72mm Circular is the common choice. If you intend to shoot at the widest angle the edge of the filter will appear in the corner of the frame, so "72mm Circular Wide angle" is designed to reduce that effect (however you can attach any more filters when using this variety.)

You can find them on Ebay fairly often. Search "Tiffen 72mm filters."

For this kind of camera a liinear polarizer will do the job. A circular polarizer will cost you about twice as much because it needs a retarding layer to achieve circular polarization. But since all light measurmenets and auto-focusing is done based off data from the CCD block, the circular polarization will give no advantage. (unless it's just a higher quality filter in the first place)

-Steve