i see what you did there. Awesome.
Mod funny please.
Oh come on. A properly patched network with a good firewall will work just fine. I run a multi-site network spanning 3 continents with very high uptime and very few problems with viruses. Our biggest security problems are things like people losing USB storage devices (we started encrypting them though, so that's less of a worry).
The tricks are as follows:
1: Good firewalls with IPS/IDS services
2: Hosted anti-spam solution
3: GOOD antivirus that's updated regularly
4: No local admin privs for any users
5: All admins have 2 accounts - their domain admin account and their local account
6: Enforce strong passords
7: Chop off the hands of anyone caught writing down passwords
8: 2-factor authentication
9: Segregated network (VLANs etc)
10: Whole disk encryption
That's a reasonably secure network - sure, there are always ways in for someone that's REALLY determined, but Windows networks CAN be made reasonably secure with a fairly standard set of practices that translates across any OS.