I'm working on some wireframes and I've heard that just to the right of center is best for the primary object on your website. Is this right? and if not, where is the best place to have a 'call to action' button (or other primary object)?
There is no one place which is best to dedicate for call to action. Depending on your design you will end up with a good place suited for that design. Some of the most common placements for call to action buttons are (Smashing mag article: Call to action buttons, examples and best practices):
Some higher level considerations, including position, for call to action buttons
I would like to know how you came to the conclusion of 'right of center'. First time I've heard that.
I agree with rk. that the placement of your CTA button is dependent on your design. If the scope of your project is quite large, in that the website you are creating will be relying on templates, you should place your CTA buttons in a consistent location across all of them. Of course, there are pages, such as landing pages that can be an exception.
I recently came across Jakub Linowski's GoodUI.org page which explains the basis behind a good user interface. That is, a good UI results in high conversion rates and is easy to use. Hope that helps!