Question about backing up MultiBit wallets

[tropicalmonsoon]

Hi everyone... I've got some bitcoins in a MultiBit wallet, and I read on the MultiBit website that you can backup your wallet by simply copying the .wallet file, the .info file and the -data folder into other directory (USB stick, CD or whatever). However when I went to backup mine I saw there was also a .key file, which I assume is because my wallet is password protected. So my question is: Does having a password on your wallet interfere with the ability to restore it if my hard drive gets wiped or something? Do I need to copy the .key file over too, and if I do that will it ensure that I can restore my wallet from that backup?  (This is all assuming I remember my password, of course).

Thank you!