Equipment a paranormal investigator uses on an investigation

Paranormal investigators employ a wide range of equipment on investigations. Our equipment can range from the simple flashlight and notepad to elaborate FLIR cameras, REM pods and spirit boxes. Some of us claim our digital camera or DVR as our most indisposable piece of equipment. To help clear things up for the new investigator just starting out I am asking, in your opinion what one piece of equipment yields the best bang for your buck.

I voted for the digital recorder but of course you need the computer to analyze anything you may have picked up later, so they go hand in hand.