Hello GeoBible, and WELCOME to SatelliteGuys.US FTA/MPEG-2 forum : )
Yes FTA TV is perfectly legal in every way and I think it would be ideal in your position, you would need at least a 30" dish, a receiver and a LNB.
There is no need to hook these systems to a computer as they come with the latest software already loaded and should last for quite some time, the only time you would ever want to hook one to the internet world be to upgrade the firmware to the latest version.
I like the Fortec Star Lifetime Ultra System, with the 90cm dish, it comes with a Universal LNBF and a self install kit, so more or less everything you need. I would also recommend a H to H motor to take full advantage of your system and to pick up as many FTA channels as you can, there are LOADS up there including all the networks right now.
You may be able to use your old Dish 500 dish to get an extra few channels and radio, but you will need the bigger dish for most of the FTA broadcasts.
Computer cards are great but right now they do not have the BLIND SCAN that the receivers have and is really a must have feature, its a lot of fun and could be all the TV you ever need it is for me, any more questions let us know you found the right place for advice and all the help you need to get your system up and running, take care!