James Padolsey writes at the learningjquery blog about the way to make a jQuery Plugin customizalbe. Basicly it’s not about how many options your plugin has, ist about what options it has.
It all goes down to three points:

• Flexibility: How many situations will your plugin be able to deal with?
• Size: Does the size of your plugin correspond to its level of functionality? I.e. Would you use a very basic tooltip plugin if it was 20k in size? – Probably not!
• Performance: Does your plugin heavily process the options in any way? Does this effect speed? Is the overhead caused worth it for the end user?