I currently have my status line set up so that it\'s orange in insert mode and white otherwise. I\'d like to make it go another color when I drop back to normal mode if the file
I like the idea of using the statusline color to indicate the buffer state. In fact, I've written the StatusLineHighlight plugin, which indicates the following attributes: modified, readonly, unmodifiable, special non-file "scratch" (but not the insert mode that you're using; for that, I find Vim's mode indication in the lower left corner enough).
I think that you are looking for
:echo &mod[ified]
which returns 1
if modified and 0
if not modified.