Well the canonical will be different for every page...so if your page is:
www.jeremygower.com/contact/index.php
your canonical would be:
Basically, what that says is..."hey google, it doesn't matter what URL you think you're at, make sure that the only one in your search engine is the one in the canonical tag"...therefore, be very careful with it as well. If you simply put www.jeremygower.com as the canonical for every page, google would de-index every other page of your site.
Anywhere in the head is good.
IMO, unlimited ends up being a bad thing...the way those things work is that godaddy (or whoever) puts a ton of websites on the same server, so think about the 500 or so other sites with 'unlimited' bandwidth using your server. It makes it slow...for instance there's about 400 domains on the same server as my domain, and yes, it's slow a lot of the time...the cheap plan on a small orange I'm sure is similar but I'd expect better quality than godaddy. (they dont have unlimited)