Hi OldBaldguy,
"...Plenty of devices out there that will let you do Over the Air TV to your computer..."
What would such a gizmo be called so I can google one?
"...You need hefty computer processing power..."
How hefty???
The computing power required to decode the DTV requires a Pentium or Athlon processor running at roughly the following speeds,
600-800 MHz for viewing DTV
800-1 Ghz for viewing and recording DTV (turns your PC into a powerful digital video recording machine)
2.4+ GHz (Pentium) 1.8+ GHz (AMD Athlon) for viewing HDTV
These computer speeds are for European DVB-T with an internal PCI card (fitted inside a desktop computer) but the US DTV standard will be somewhat similar. A slightly faster PC would probably be required for USB connection. USB 2.0 standard ports should be used as they are much faster than the older USB 1.1 specifications.
Any of the new Dual/Multicore processors (AMD or Intel) should have no problem with these DTV decoders. (either PCI or USB2.0)
There are now quite a few graphics cards designed to do the most of the brute force decoding of the DTV signal and put the video out on a HDMI connector for the large panel HDTV LCD televisions.
I personally have a Nebula Electronics DVB-T HDTV PCI card in the back of a declocked 1.8GHz Athlon XP running at 1.24GHz with 1 Gig of memory and it works flawlessly.
http://www.nebula-electronics.com/shots.asp shows some DVB-T screenshots
The Nebula Electronics DVB-T adapter will also allow the PC to become a network Video server allowing the video stream to be re-broadcast over a home network wirelessly and over the Internet (the ability to login into my DVB-T video server from any other PC in the world with an internet connection to setup recording and view British TV from anywhere in the world)
(I'm looking to soon upgrade the motherboard and processor to an Athlon X2 EE 4400 processor and Gigabyte AM2+ motherboard to reduce power consumption to around 30-40 Watts after declocking)
Typically channels such as BBC1 (one of about 50 free to air TV and 20 Radio channels) are transmitted as 15Mbps Video and 256kbps Audio so the video bandwidth is actually greater than DVD standard (with virtually no compression artifacts)and Audio as good as CD.
Then of course there is always BBC iPlayer at
http://www.bbc.co.uk/iplayer/ just in case you have missed the latest episode of Dr Who.