Do I need a special TV for my touring caravan?

The standard small TVs work just fine.  Don't get a big one though as you will not be able to sit all that far away from it.  The power consumption is very low so they can be easily used running from 12v - many are actually based on being 12v anyway and have a plug top power supply to run it.

Aldi/Lidl have sensible offer prices, and some folk have mentioned Asda and Tesco as well. Depending on the age and construction of your caravan you may even find a bulkhead to fix a bracket to.

One of the main benefits of the Avtec is the wide range of angles it can be viewed from. They are certainly not the cheapest, but it does depend where it is located. We found the cheaper type great when you were directly in line with the picture on a similar level, but picture quality suffered when viewed from an angle or below.

It seems that ordinary sets are OK although most are mains only. I brought an Avtex caravan set because I hope that it is designed for the rough and tumble of touring life. It also works on 12 volts and has a built in CD player. 

Dearer yes; worth the extra? Ask me in ten years time.

One of the main benefits of the Avtec is the wide range of angles it can be viewed from.

Seems a good reason to choose one Steve. Not for us rarely used.

It will depend on how you plan to use your caravan.  If you are only going to use sites with EHU then get a standard tv.  We used a 19 inch domestic tv bought from Tesco for many years.  If however you plan on doing rallies with no EHU then you will need a tv capable of running off your battery, like the Avtex.  Since we changed to a motorhome we have had an Avtex tv and find it excellent.  Expensive compared to a normal domestic tv though.

It is still possible to buy standard TV's with an external power supply and use a lead to run from the battery.  If I remember correctly our 22" Samsung cost us arround £130. Excellent viewing angle HD. Addmitdly no DVD but we play films from a memory stick.  Compare that price to an Avtex TV.  

If only going to use on EHU a standard flat screen tv is fine we have a 19inch from Tesco £95 in a sale does us fine and we are in our c/van a lot 6yrs now

Ps including HD and DVD

We have a Samsung 22" as well but bought a cheap DVD player to use when needed. I think the DVD was about £25 and the TV£129 in a sale. You can also use a USB memory stick with it as well. Good viewing angle as well. Like the OP only use electric hook ups so no problems.

It's 'horses for courses' really, if you want a TV that will work anywhere then an Avtex is worth the extra money as it is designed for 12v and can work off a digital aerial and/or a satellite dish with no extra boxes etc.  If you are happy to watch TV only when you can get a digital signal and only on EHU then a cheaper 'normal' TV will serve you just as well.

Although you could probably buy a cheap portable satellite system and a cheap small TV for less than the cost of an Avtex, you would then have a lot of wires and an extra box to site somewhere and power, but that is an option.  

We 'inherited' our Avtex with the van and while it's a great bit of kit, 'live' TV isn't that important to us while we're away, so if I had to buy myself I'd probably go for a cheaper mains only TV.