I'm sure a lot of people have faced this. Switching your web site from a 100% basic HTML site over to all php files. Basically what you're doing is getting rid of all the files that exist on your site with the HTML extension and replacing them with pages that have the php extension. Doing this causes you to lose all your sub-pages' PR. There are several options to fix this, one being the meta refresh, one being the 301 redirect and one being mod-rewrites.

The meta refresh tag is not necessarily the most search engine friendly method, and neither is a 301 redirect and the problem with these methods is that your new pages start off with a zero PR anyway and you have to wait until the next PR update to see any change, and even then there's no guarantee you'll end up with the same PR as the old page.

The mod rewrite is the best solution, I think, as your pages can still look as though they have the html extension, but the file name is being drawn from a php file.

Anyone else have any other solutions?

I would go for a 301 redirect because it's the most SE friendly redirect.

But the mod_rewrite would be the route to go if you are still concerened about SEO because no URL's would change.

just make .htm/.html files be parsed as php

Nothing changes, no redirects needed.