but with broadband most people have a stealth mode NAT router in the way (in order to service several machines in the house) and that'll stop quite a lot of incoming.
Sorry, I can't resist biting on this topic !
What a load of drivel.
(a) Repeat after me .....
Security by obscurity is NOT security .....
(b) In 95+% of the cases I've seen, viruses have appeared on someone's computer due to their clicking on dodgy attatchments in emails or some such, whilst at the same time having inadequate virus protection.
(c) So, you might have inbound blocking. But let's say you do have a zombie vrus on your PC. What are you doing to stop Dr Evil launching a DDoS attack on
insert name of well known website here using your computer as one of the "bots". And don't you even think about telling me they need inbound access to your computer to control their bot, they don't.