I want to delete everything out of my template files but I want some plug-ins to still work. How do I know what I can delete?
The bare minimum would be to have just index.php - delete the get header, footer, sidebar code. Practically everything can go except for the loop and show contents commands. It'll be the ugliest page on the web but it will work.
It really depends on the plugins and how they work. Most will not cause any errors but some expect to find certain parts of a template.
those widgets won't be happy without a sidebar and you'll probably still need functions.php what are you trying to achieve... might be able to give better advice if we know where you're heading.
I need an empty page in wordpress so I can use php to generate the page completely (header, footer, content). I need to use wordpress so I can use an adsense plug-in.
Forget wordpress altogether... adsense isn't hard to add to a page and if you have the php skills to generate a page you have the skills to cut and paste code from the adsense website too.
Agreeing with above, but for future reference the bare minimum for a WP theme to work is actually index.php and style.css, as style.css is where WP finds the theme name etc.
Indeed! I was thinking more of getting the classic theme and stripping back index.php rather than creating a new theme or of discarding files.
<?php wp_footer(); ?> must be in the footer.php right before </body> while <?php wp_header(); ?> must be in header.php right before </head>. Without these two hooks, most wordpress plug-ins will no function. Please take note