This question about the compatability of Plugins, WordPress Software, and WP premium template was brought up by John from LMU. There are a lot of great plugins out there which are compatible with older WordPress software versions 3.0 and older. The problem also arises when you update your WordPress software to the more recent versions and suddenly your favorite plugin doesn’t work. For example Contact plugin is my favorite and this software gets me lots of work. My advice to keep your favorite plugins is to start with the earlier versions of WordPress and upgrade when necessary.
Also when buying premium WordPress templates, there is always the benefit of getting a free plugin as part of the WordPress package. Be sure to contact your WordPress supplies as to the compatibility of their themes with the latest WordPress software like 3.1.