When searching the literature for material to support my own research, Google Scholar is an indispensable tool. Still, there are many articles that look promising, but to which I do not have electronic access (even through my own institution's library).
Self-archiving is a great idea, but many authors do not make their work available in this way. Even if they do, it is often very difficult to find... the availability of the paper on a personal web site does not mean I am going to find a link to it in Google Scholar search results.
One way around this is to self-archive your papers at Selected Works, from Berkeley Electronic Press. This commercial project offers free web pages to individual academics where they can post their own work, and the best part: Papers posted at Selected Works are indexed by Google Scholar.
In preparing for this post, I was testing out whether I could find papers I knew were self-archived. Michal E. Smith, a Mesoamerican archaeologist who is a big proponent of self-archiving (and the creator of Publishing Archaeology), makes his papers available on his own website. I searched for some of these papers using Google Scholar, and found PDFs of them... not on his own page, but at his Selected Works page.
Self-archiving on your own university website is fine (and everyone should do this), but with Selected Works, you get an easy, professional-looking way to make your downloadable publications available and findable via the internet.
Financial viability of open access
You should self-archive your publications