If you ever intend on using a CD32 controller or a Playstation to CD32 adapter, so you can use all seven buttons instead of just two, you'll need one of AmigaKit's newer Joy/Mouse Switchers. I've tried two older models that have been around for years and they don't have all pins connected and won't work with the extra buttons on a CD32 pad.
http://amigakit.leamancomputing.com/catalog/product_info.php?cPath=42&products_id=961
