Is it legal to use a company's logo for your personal use?

Assuming the logo warrants trademark (or tradename, etc.) protection, then yes, it is illegal and it would be trademark infringement. Only the holder/owner of a mark may use it for any purpose, or allow others to use it. Someone who uses a mark without the owner's persmission, even for non-business, non-money-making purposes, is guilty of infringement and potentially liable to the mark's owner. Note that even if a mark is not registered, it may still be a valid, enforceable mark if it is used in commerce to identify a company or source of goods--pretty much any company logo should be assumed to be a protected mark.