Wanted to know if anybody knows the answer to this question.

When you use your meta tag data as a php include (so that it'll appear on each page and can easily be changed in one file), will it still be readable by spiders and bots and still be effective and recognizable?

When PHP generates the page and serves it to the requester, it would give all of that information to the requester.  So if you are using it as a PHP include, it will be there for the spider as it would be for the regular user.

Yeah, I actually just made each individual page with its own individual meta tags. I think its better that way, so that the bots can correctly categorize every page I have on my website.

Yuppers...

Often all of a NEW or even existing site can end up supplemental except for the MAIN page if ALL of the meta-descriptions are the same. Happens a lot actually..even some larger sites I know of are almost TOTALLY supplemental... doh!

I would do it the way you have with UNIQUE meta desc. for each page. (or targeted pages at very least)