Found the problem and have the solution, from the entire process just in case this might help anyone.
1. Went into IIS and noticed that the PHP FastCGI module was installed for my Web Site, but not for the Webserver as a whole. Deleted the child FastCGI module and reinstalled it as a module for the entire site. This resulted in actual verbose error messages.
2. The verbose messages were a 500 error - FastCGI stopped unexpectedly (error code 0x000000ff). Further investigation of this error led me here - http://forums.iis.net/p/1149374/1869613.aspx
3. Noticed this user was a having a problem with a missing .dll referenced in the php.ini, which I was also having a problem with. Didn't think much of it since command line PHP worked fine and it displayed properly in Firefox, but went into php.ini and commented out the line for that dll.
4. Works like a freaking charm.
Go figure. Hope this may help someone someday, I know I lost some hairs the last few days trying to figure this out.
Daniel