I am currently testing the e-commerce plugin Eshop.  It is very simple to install, uses Paypal and can handle digital downloads.  So far I am satisfied with the plugin but will need to do more testing. Here is a review that I found on Eshop: http://www.articlealley.com/article_847900_15.html

WordPress is my platform of choice when designing websites and blog sites.  This is a freeware/open source program that is continually being improved on.  This makes keeping websites based on WordPress up-to-date a challenge.  There is a plugin that solves this dilema. http://techie-buzz.com/wordpress-plugins/wordpress-automatic-upgrade-plugin.html Backs up the files and makes available a link to download it. [...]