Can someone confirm my security is OK?

[halfawake]

...disables autorun to protect from a USB transfer virus, and encrypts the offline computer with a strong password to guard against physical use he is perfectly safe (provided his paper backups remain so) because the private keys to spend coins are not accessible to the outside world, period. It doesn't matter if the online computer ever gets infected. No coins can move without being signed by the encrypted offline computer.

These are really the key points for securing the offline computer, particularly disabling autorun from USB drive.  Just running Linux rather than Windows on the offline computer will help, but disabling autorun should take you 90% of the rest of the way there.  Encrypting the computer?  Sure, if you're paranoid enough, go for it.

[cp1]

I have recently installed Armory on my everyday PC, plus on another machine not connected to the outside world. I've created my wallet on the offline machine and a watching-only copy which I have imported into Armory on the onliner machine.
I have a paper backup of the wallet printed (immediately after installation) which I will keep safe in multiple locations.
I've transferred a quantity of BTC into the watching-only wallet.
Anything else I need to do?

As long as that offline machine was a clean install you're good.

[D35TR0Y3R]

use brainwallet

[GiganticDays]

Just one last question about my paper backup (noob) - do I need to create a new backup after transactions, or is the initial backup good for life?

[dancupid]

Just one last question about my paper backup (noob) - do I need to create a new backup after transactions, or is the initial backup good for life?

It's in theory good for life - but you need to make sure when you make a transaction from a paper wallet address that the change is returned back to the paper wallet - if you're not careful it will  be returned to an address you were not expecting.

[Otoh]

Just one last question about my paper backup (noob) - do I need to create a new backup after transactions, or is the initial backup good for life?

It's in theory good for life - but you need to make sure when you make a transaction from a paper wallet address that the change is returned back to the paper wallet - if you're not careful it will  be returned to an address you were not expecting.

This is very much easier to manage if you use blockchain.info wallet for the TX rather than the BTC client one, not sure how easy Armoury wallet makes this as haven't tried yet.

[cp1]

Armory is deterministic, so you're good.