PR is definitely not that important. Rankings are what matter.
As to your questions, a sitewide link is only marginally better than a home page link. The SE's will give you credit for the "best" link on a specific domain, but the 2nd, 3rd and so on are not given much weight in the algorithms, though they may give a bit of extra juice. It doesn't hurt to do sitewide, especially since you never know if the home page is the strongest, it usually is, but in this industry you might be surprised to find that a sub-page is stronger.
Article links are fine, but you need to have a lot of them to equal one well placed home page link. Plus, you really need to have unique articles for each link which equals quite a bit of work, though article spinning can help reduce that effort.