Lots of people ask, now and then, whether they should have a "Home" button on their main menus. They ask whether it's redundant (and therefore maybe confusing) when the user is actually already ON the home page, or if it's redundant if the logo is clickable to home (which is very very common on the web, and therefore can be considered a web design "standard" (users have expectations that logos are clickable and go home because so many sites do just that).
Item number 43 has caught many people's eyes for example.
Epic Bagel did a usability study for a client who removed the Home button from the regular navigation, leaving the clickable logo as the only way back to the home page.
You (probably) still need a Home link (this is a blog post about the result, not a usability study itself).
Interesting stuff! Especially as I'm finishing up two site redesigns: one has a Home button, and one does not.