It's a good enough iPod. Nothing wrong with them, but if you're going to put it in a permanent enclosure, I'd consider replacing the battery first. If it's removable, then don't worry about it just yet. Mrs Pugwash had the 1st gen and it's probably still working, but she uses an 80GB Classic in the car and a tiny latest gen Shuffle for the gym.
I don't know how you can compare it to an iPhone. It's nothing like it.
http://support.apple.com/kb/SP25
Picture: http://en.wikipedia.org/wiki/File:Ipod_nano.JPG
Get a Ziplock bag for your phone (sealable sandwich bags at your local supermarket) and use that a your camera. I have a waterproof cover for my SLR which comes in useful at places like Silverstone where rain is inevitable, as can be seen below.
Looks like the extra crown is for turning the bezel. If you do cannibalise that watch for the movement, try and keep the old parts safe because I like the old Longines.
Those sound like aftermarket rims. 2.2 bar would be be settings for the normal 60R18 tyres, and to be honest, that should do you fine too.
http://www.tyre-pressures.com/ByCar/MAZDA/CX-7/5+DOOR+ESTATE+-+6+SPEED+MANUAL+-+PETROL/16V/2261/07+MAY
The reason this one is actually a car is that the engine is powering the wheels, as opposed to being a buggy with a jet engine on it. If you stop using car technology, you can go way faster than 426mph.