Are you using the Properties Tab Builder, you can have drop down lists in there.
In the part you can set up a list of your favorites in materials and have "SW-Material" as the material property.
( Save the material property desciption in your part template )
Yes this looks to be exactly what I'm after. I wasn't aware of it's existance in SW2009. Thanks
What version are you running? The Property Tab Builder that Michael mentioned is probably your best bet, but it was introduced in 2009.