Title and alt on the site logo.

Hello all.

Here are two scenarios which I would be interested in hearing opinions on from list members. They involve "logos" on a site.

From a usability point-of-view it is suggested that linking a site logo back to the home page of the site adds usability value.

However, in doing so the link may now be apparent through the value of the alt attribute (or title if the logo only text).

What, then, is th ebest suggestion for populating these attributes. 

for example   
alt="Site Name: link to home page." 

and obviously if the logo was textual, should a title of 
title="links to home page"
suffice?

Tim