I recently had all of my 450 indexed pages erased from Google's Search Listings? How does this happen, I have not been doing anything shady, has someone spammed my site or what?
That sounds very odd. I've never heard of this before. I will do some research to see if I can find anything.
Check your webmaster tools if you have an account there. If not try contacting Google directly and asking them why your website was removed.
1. Is your site has totally pages for 450 pages? Or 450 pages is just a part of your website? 2. Is your website ranked #1 when type domain without extension? 3. What have you done on your website recently? Did you do any gray or black hat kind of seo?
Investigate thoroughly about your site's past activities, if you suspected some errors or inappropriate link building done, take actions to correct and remove them, then send a request to Google about what happened and your request for re-inclusion.