When I send a bitcoin does all of that coin's value travel 1 for 1 or does some of it get used by the system..
The bitcoins aren't used up by the system. The transaction fees are going to other users of Bitcoin who are running mining software that helps find new blocks. Think of it as subsidizing their electricity/hardware costs, if you will. But those coins aren't "vanishing".
ey! Newbie here been lurking for a few months. Are they lost forever if you have a printed out version of the keys. In other words, i've seen people recommend this and assume if you hqve paper backup you could reconstruct wallet.dat
Anybody actually tried this or just a persistent myth?
If you have your wallet.dat then you have your wallet.dat, and you can still get access to the money. Most people recommend storing an encrypted backup on a USB key though. I will admit that paper is probably more durable (well, assuming acid-free archival paper anyway), but recovering from that would require a bit more work, either in manual typing or scanning and OCRing, than if you just kept a backup on a USB stick.
If you keep your backup in the same physical location you're still vulnerable to loss by fire and such. A lot of people recommend strongly encrypting your wallet.dat (I would recommend TrueCrypt for that) and emailing it to yourself. That way it'll be stored on, say, Google's servers, and it's unlikely that your house will burn down on the same day as Google suffers a catastrophic loss of information, including all of their backups.