It would be nice to know, how secure the system really is on OS level, without an 3rd-party (or Windows build-in) firewall. Of course it would be easy to test with online security tests, BUT i don't like the idea to shut down the firewall, while connected to "big bad" internet.
Can Windows be safe (from incoming attacks), if it's just (fully) patched and securily "tweaked"? Basicly, why to update Windows, if you run an decent firewall...? Of course it's good to update, but i mean basicly...