trailing slash for collection URIs?

Hi,

this might be a hard to decide question like spaces vs. tabs: I might have an 
addressbook web application that has mainly two sites

/myapp/contacts (or /myapp/contacts/ ?)
/myapp/contacts/{id}

Should the /myapp/contacts URI have a trailing slash or not?

From an implementation perspective I like the trailing slash so that I can 
just use the contact id as a relative URI from the collection resource. But on 
the other site a collection might also be a resource?

Thank you for any recommendation!

Best regards, Thomas Koch