We have a 42 inch Philips Ambilight t.v. We love it but I wouldn't recommend you spend much more than you intended to just to have it as an extra feature. It can be left off if you like but we like to have it on. It just creates a nice background light behind the tv but to be honest you should decide if the tv meets all your other requirements and wouldn't base my decision to purchase on what essentially is a gimmick. On the plus side, it looks great and everyone who visits us comments on how great it looks.
thanks a million voyager, it was a 42 inch i was looking at, it fits our requirements other than the ambilight, thats great you can turn it on and off if you want, thanks for your help
We've got a 32" Ambilight and love it, well worth the extra few euro. Was a bit sceptical at first but it does make a difference, just make sure you turn it down to about 30%, its a bit bright otherwise.