Where a hacker wants in, he will get in. That is the first lesson in any respectable security school. With that in mind you goal should be to make it difficult enough to appear to "not be worth the effort". You have a good base security setup for a home user. Norton Internet Security is a very good protection package, but it's only as good as it's policies so be sure to look those over for only what you need. The wired router also plays a good part in that it is a NAT which can somewhat mask your network behind it making it that much harder to break into and navigate. With sharing your drives you should be careful and assign access by username and password and that should be sufficient. The biggest concern with the shared drives is someone working inside your local area network such as a wireless connection.