I think Footer link or blogroll links are better because content links can be hidden from the front page because of adding new content to the site.
Links in Blogroll are more effective First because It will be shown in all pages and other sites links in content is more effective .Because It will be exactly in the position where google spider give most preference that is in content. other links on header or footer may be consider as spam links
Hi there; Links in both places if you can do it; Some article directories allow it, some don't and- use anchor text with your keyword in it. It is good on your blog or website. Just make sure the content flows and you do not jam or spam a keyword in there just for the sake of getting a link in there. All good; The fall guy Phil