Anne,
Yes my rule of thumb is always 'lowest common denominator' too many people create sites that use Java, Flash and lots of other trickery and do not consider that many people do not have these features installed. You do not want to limit your market by creating technology wise leading edge sites that people cannot view properly. Stick to the basics, hey you dont have someone guiding you round Argos or woolies jabbering in your ear so why would it work on the net?
Gary