The manual with my Sony HC1 simply states "NTSC" as the format, but the menu for iMovie lists several variations of NTSC, which is the right one for my HC1 in HD?

Assuming you shot 1080i ... The HC1 records HDV. In FCE, go to Easy setup and look for something that says 1080i HDV. If that isn't listed, use the Apple Intermediate Codec (AIC) for 1080i.