I don't see the licence fee as just for TV - as someone who enjoys a lot of BBC radio that simply wouldn't get made (or certainly not in such excellent depth) by commercial broadcasters, I think it's a fair fee.
Add the wonderful TV dramas and documentaries that provide a true public-service remit (not to mention one of the best news websites going) and the Beeb is worth it, IMHO.
Sky serves a different purpose - more of a high-quality delivery platform than a content provider. Again, worth investing in if you want to enjoy your entertainment in the highest-quality (ie HD) format.