After You find the wallet.dat and back it up, read further.
Hey guys, I understand that if I make a copy of my wallet.dat file I will never lose my bitcoins.
This is not true. First thing is that wallet.dat initially generates 100 addresses (private keys). The wallet backup is good for some time until these addresses are used up. I suggest the wallet.dat to be backed up regularly using different file names or folders, to keep all versions of wallets organized in case of corruption.
Also the coins can be lost if someone hacks the computer and gets the wallet or private keys.
Exactly. Remember that if ANY of your wallet.dat copies are compromised, all your coins associated with that key are at risk, no matter how many backups you have.
Encryption+offline storage+backups seems to be pretty a good practice to me. It's also important for the system you create the key/use your wallet on to be secure as well.