The license fee is effectively a tax, which gets used to fund a national broadcaster.
Personally, I believe that it's crucially important to have a broadcaster that is not bound purely by ratings figures, and is actually obliged to be impartial and educational (it's in the BBCs charter which is renegotiated and evaluated regularly - and it's not a foregone conclusion each time either). There are lots of 'reality TV shows' around, on the BBC as well, but it's actually rather interesting to note that a lot of the ones on the BBC are rather educational and interesting, as well as voyeuristic. For example, if you are watching say 'Bank of Mum and Dad' you might be watching just to see the wreckage of people's lives, but the way the show's made you learn a lot about psychology (the psychology of denial in this case) if you look closely. You might even argue that the viewing public would learn this subconsciously. Some shows on foreign or commercial TV simply set up arguments and conflicts for the sake of watching people argue - which isn't educational at all.
I do believe in public service broadcasting as a concept, and the fact that it is funded through non-commercial means is vital. But then again, I am a lefty who believes in spreading the light.
I think it's most definitely true though that the BBC has raised the bar in the UK for TV. Most other countries have absolutely crap telly - many many people have said (on here too) how bad telly is in other countries. Yes, we watch a lot of American telly but to be honest it's mostly formulaic, unoriginal and we only see the best 5% of it anyway. There is an incredibly vast amount of pure sh*t on telly in the States, and even that's better than most countries.