OK - who has bought one of these lately. I have suddenly been thrust into the purchase world for one and it's soooo changed!
Welcome to the party Granddad!!
I know I want a flatscreen, full HD digital TV, not fussed about 3D. After that it gets about vague.....
Plasma uses lots of power, ours literally heats the room! Plasma is generally considered to have a better picture than an LCD TV but this is changing. I think Plasma's are now reserved for sizes which are too big for an LCD.
Up to a certain size, a modern, good LED/LCD TV (that's an LCD TV which is backlit with LEDs which is what modern consumer TV's are) is going to look as good as a Plasma, it'll also be thinner, look more modern and use a fraction of the electricity.
Good size of screen these days?
Really depends on your room and what you'll be using it for. If you love spending an evening in with the Mrs with the lights low and a good movie on then you'll probably need the biggest screen that realistically fits in your room.
However, given your circumstances, you'll probably need something around the 32" range as Junior doesn't need the full cinematic experience for watching Teletubbies.
Other gizmos to look for? I saw one today that had skype and iPlayer facility on it - do most have these?
Not most, just some.
I'd recommend either a Samsung or a Panasonic. Try and find a shop that will let you have a play and has them wired up to the internet and other media sources. The extra £50 spent there rather than the internet could be worth it.
If you have a PS3 or a lot of other sony equipment then one of the Bravia's might be worthwhile as they have ability to all talk to each other. There is/was a Bravia which does something fancy with the wires, basically means you only need to have a power cable going into the TV which is good for wall mounting.