Some other extras, which I did not spot in the list so far.
- A small LED torch. Invaluable if you breakdown on a dark country road / cycle path - not just for fixing a problem but also for being seen. This is assuming you don't wear one of those head fitting LEDs as part of your normal gear.
- The obvious cellphone including some emergency numbers and possibly your bike frame number
- A £20 note in a plastic bag in case someone mugs you of your wallet or you fear losing that wallet
- Some first aid plasters in case you tangle with some brambles
- A whistle which you can use to attract attention.
- A hidden spare set of keys.
This thread has got me thinking... and I must renew my own kit bag!!!