SSL Certificates "www." or non-"www." ?

I'm wanting to apply an SSL Certificate to my WAMP/Joomla/Hikashop site and need to choose either a "www." Certificate or non-"www." Certificate. I can embed a redirect into the site for whichever is more appropriate, but wondered whether Hikashp had a "natural preference" for either "www." or non-"www."

Many thanks for your advice,

Robert