UNLESS you have implemented some pretty sophisticated security
Keef, given your IP address any reasonably good cracker (I'm only an amateur) could root your box within a couple of hours and you'd never know it.
And if you've got something I want, then your IP address is findable.
Linux is a bit harder than Windows, but unless you have a specially hardened install like Bastille Linux -
http://www.bastille-linux.org/ - or SELinux -
http://www.nsa.gov/selinux/ - there's a way in. And even then.
Is it worth it for the average Joe? No. Crackers are like a guy walking down the street twisting doorknobs, there are plenty of houses wide open, with everything unlocked and CC numbers for the taking. Easy pickings. If the door is locked it usually ain't that hard to break in, but it's only worth the effort if there's something you want specifically.
Don't fool yourselves, if the pro's really want access to your box your amateur security is nothing, all it does is keep casual snoopers at bay.
And if you never connect to the Net, it's easy to break into your house and steal the whole PC to bust at leisure. You can even sell it afterwards
