Usually the amount you log depends on the kind of error. The more critical the more you log.
In regards to other stuff you would want to log
- Filename for the file that caused the error would be high up the list, with line number.
- Stack trace information if the error was a result of an exception being thrown.
I don't think you can overkill the amount you log when an error occurs as long as its useful. The only time I have seen logs become really bad is when massive logs are being taken even when an error does not occur.
Some more information can be found on the OWASP website - Error Handling and Logging.