You will get BBC HD and ITV HD plus hundreds of SD channels, including those from BBC, ITV and Channel 4. Most Freeview HD boxes also provide the BBC iPlayer - this requires an Ethernet patch cable connection to your home router. You can enter an England postcode to a Freesat box to access ITV1 HD outside England and Wales.
Option 2 - Freeview HD, from £99
If you live in a television broadcast region that has switched to digital only transmission (including all of Wales and South West England) - you no longer have any analogue television - or you live in an area with the Freeview HD early service (such as London and Birmingham) you can use Freeview HD.
All that is required:
connect the Freeview HD box to your rooftop TV aerial
connect the Freeview HD box to your HD Ready television with an HDMI cable.
Plug the Freeview HD box into the mains
You will get BBC HD, ITV1 HD (except Scotland, Northern Ireland), Channel 4 HD (S4C HD in Wales) plus all of the other Freeview channels you could get before.
Option 3 - Freesat HD, no existing dish, from £148
If you don't have a dish, and want to watch HD but do not wish to record (or timeshift) your HD viewing, it costs less than £80 to have a dish installation for a single Freesat HD set-top box.
Most people can have dishes installed, and the engineer will also attach the Freesat HD box to your HD Ready television. See option 1 for the list of channels.
Option 4 - Freesat+ HD recorder, existing quad LNB dish, from £199
If you have an existing satellite dish with a quad-LNB (basically, it has four outputs) - perhaps you have (or have had) a Sky+ box - then you can fit a Freesat+HD recorder in place, or in addition to, a Sky+ box.
If you have a Sky+ box with an expired subscription, this is an excellent way to provide HD.
The process is:
Power off the Sky+ box and disconnect it from the mains, the two satellite dish connections and the SCART cable;
Connect the Freesat+HD to the two satellite connections;
Use an HDMI cable to connect the Freesat+HD box to your TV
Connect the mains to the Freesat+HD box.
If you have a Sky+ system, and wish to use the spare two outputs from the quad-LNB on the dish, this will require two satellite-grade coaxial cables to be fitted, which can be done DIY, or professionally.
Option 5 - Freeview+HD, from £285
Freeview+HD devices only require connection to a single TV aerial, so you can use as many of them in the home as you like. However, being the most recent to market the boxes are currently around £285 (Philips Debuts Freeview HD PVR - ITProPortal.com).
This price will no doubt drop over the coming years, but the first boxes also provide many additional facilities, such as playback from memory sticks.
Option 6 - Freesat+HD, no existing dish, from £309
If you want to have recording and live pause facilities with your High Definition, then a dish with a quad-LNB and installation will cost from around £110, to add to the £199 cost for a Freesat+HD box.
Option 7 - Sky+HD, from £336 PER YEAR
Another option is the Sky+HD package, as this features a "free" Sky+HD box and "free" installation, at a quite reasonable £336. You only have to subscribe for the first year, but if you continue this will be for at least £336 in the following years.
Sky HD does provide a number of additional exclusive HD channels, but the box will not record or play once you stop your subscription.