To Lakerman's father: How do you do, sir. I'd like to inform you that "opening ports" is not a risky affair so long as you don't open everything. Users have experienced security problems because they had allowed access to ports for server functions, such as port 80 for web service or 149 for NetBIOS, where there were holes in software that users never updated because they didn't use it. Opening ports in the range below 5000 is potentially risky. Above that range, if moderation is used to select the ports, it is in my opinion quite safe for you to open them.
Please note that closing a port does not prevent outside connections, but only prevents an outside machine from initiating the connection. In the case of BitTorrent, this is harmful to its function; you can see why at:
http://bt.degreez.net/firewalled.html. The software operates much better when it has a server port available.