|IMHO it is more elegant to solve the problem in the web server layer.|
Just disable all scripting for the uploaded file directory (Apache example):
AddType text/plain .php .phtml .php3 .phps .pl .cgi
"AllowOverride None" disables .htaccess scripts, which can be uploaded too.
If you have a separate server for uploads, then don't install php, perl, cgi, etc. on it and you'll be safe.