Should the word 'internet' be capitalised?

Whether or not to capitalise the word 'internet' provokes occasional debate. I used to capitalise, and then Wired announced that they were not going to do so, I changed too. I figured they knew. However, I still see it capitalised in mainstream magazines and some clients insist on capitalising it.

For capitalising Internet

There are some reasonable arguments in favour of capitalising the word 'internet':

• It's a kind of place and places are proper nouns that get capitalised
• Lots of other people do it.
• There are internets (networks of networks) but only one Internet.
• According to Wikipedia (not a wholly reliable source) The New  York Times, Associated Press, Communications of the ACM and Time capitalise it.

Against capitalising internet

• Capital letters are speed bumps for the eyes when reading. Like unnecessary punctuation, they should be eliminated where possible. (Some clients like to capitalise all Nouns and especially Multi-Word Nouns. Maybe they are German.)
  
• As Wired says 'That it transformed human communication is beyond dispute. But no more so than moveable type did in its day. Or the radio. Or television.' And all those words are not capitalised.
• According to Wikipedia, The Economist, The Financial Times and The Times do not capitalise.

My instinct is that the trend is towards the lower case. Certainly, that's my preference. Welcome to the internet.