I have windows 7 on my laptop. In the instructions above, are you suggesting that I make the USB drive wallet out of an operating system other than windows?
Other operatings systems like Linux are preferred for their security and ease of use. It's also plain more difficult to install and run Windows from a USB thumb drive than it is for Linux.
What do you mean by savings account?
A savings account is one that you don't withdraw money from very often. It's intended to be something you put money into more than take money out. That's relatively easy to do with Bitcoin because you can still put money in while you keep the private key securely locked away. You need the private key only to withdraw money from your Bitcoin "savings account".
As Bitcoins are so expensive is it ok to only buy one and put half of that coin in one wallet and half in the other?
You can buy a small fraction of one Bitcoin and split it up however you wish. They can be divided up into pieces as small as 0.00000001 of one Bitcoin, and the system can be extended later to support smaller units if that isn't small enough.
Am I right in saying, that as my laptop is only ever used by me, it is NOT classed as a netoworked computer?
If you connect your computer to the Internet, it is networked. The Internet is a large network.
Is it like this - For each transaction, you need a public address key, and a private one, which matches the public one?
To spend bitcoins, you need the private keys that correspond to the addresses that have bitcoins; those are "your" private keys and no one else's. You also need a public address (yours or someone else's) to send the money to. You can calculate a public address from a private key but not the other way around. The Bitcoin client that you created a key in will manage the private keys and addresses inside the wallet file automatically.
Am I right in hurrying to buy bitcoins as they seem to be going up all the time?
That's really up to you and what you plan to do with them. If you plan to spend them immediately, their price in the future doesn't matter. That is, if you buy $10 in Bitcoins (about 0.063 Bitcoins at the current rate) to buy something for $10 worth of Bitcoins, you'll spend the same whether they are worth $150 or $15000.
If you plan to hold on to them for some time, you ought to figure out what the risks are for you. They could double in value or they could become worthless in a week. Is that worth it for you?
I spent a small amount of my personal savings on Bitcoins; if I lose it all (not likely), it would certainly suck, but I wouldn't be hurting financially. On the other hand, if they become 10 to 100 times more valuable in a couple years (quite likely), I'll be a little bit more well off than I currently am.
I actually don't follow these instructions. I prefer to print out a "paper wallet" from a page like
https://www.bitaddress.org/ on a secure computer (that page works offline). The paper wallet consists of several private keys and their public addresses, as well as their QR codes to make it easy to scan them into a computer. Then I scan or type the public addresses from the paper wallet onto an online computer and then store the paper copies in physically secure locations like a fire-proof safe. I can send bitcoins to one or more of the addresses in the paper wallet and they'll be relatively safe. When I want to spend bitcoins from my paper wallet, I'll need to import (scan or type) one or more private key from the paper wallet into the Bitcoin client on an online computer, then I'll have immediate access to my funds. If there's any amount I don't want to spend right away, I'll send it back to my paper wallet to an address that has not been imported (the private key is no longer secure enough for an offline savings account once it has been imported).