The wallet.dat contains your bitcoin information. A backup simply creates a backup file, it's your responsibility to then make several copies of the file.
Personally I backup to the PC, then to a USB stick and external hard-drive. Every time I acquire or send Bitcoins I make a backup and date it for my own records.
As long as your passphrase for your Bitcoin wallet is good anyone hacking your computer would also need to hack into your wallet file. I recommend you also install armory for heightened security:
http://bitcoinarmory.comReally appreciate the help. I will do the above, and install bitcoinarmory for online, and offline computers. So I don't need to break up my coins into separate accounts right? Really wish I could put all my coins on an offline computer, and transfer only what I want to spend on my main account.
You obviously haven't researched enough if you think mining is a still good idea,
True, I still have a lot to learn. I was using a calculator and it was calculating that I would make around $1000.00 a month. Is this number not accurate?
Really appreciate your time, and help guys. This helps me out a lot.