What happens if I delete wallet.dat? I have this question, say I have my coins in my local wallet and 1 of 2 things can happen, say I somehow delete the wallet.dat file or some kind of malware deletes the file. I have the password private key to the wallet, would I need the wallet.dat file to recover the bitcoins or could I just recover with the private key to the address? Would I need both?
Since wallet.dat is mostly a collection of private keys, you will simply lose all private keys that you have not duplicated or copied. It also by default stores the next 100 Bitcoin addresses it will give you when you generate a new address as a safety measure.
Bottom line
You will lose the copy of the private keys to addresses you've created or added but you won't destroy them. A backup will save you regardless if wallet.dat exists or not. If you restore wallet.dat from a backup, you:

will not lose past transactions, those are stored by the network, not you.
will not lose ownership of any bitcoins you may have acquired under the private keys you backed up, generating a new one and not creating a backup may result in loss. Keep in mind first 100 addresses are stored in wallet.dat.
will not need to know the address of a public key. Those are derived from the private key mathematically.