why have grounded outlets?

I bought a house with old 2-prong, ungrounded outlets. I have quite a few computers, appliances, and a power hog plasma tv that all have 3-prong plugs. The surge protector paperwork says I need to connect to grounded outlets or the warranty is void. The home inspector said don't worry about it, that it isn't necessary and I can just use the 2-3 prong adapter. So what are the benefits of having grounded outlets? Is this to protect the equipment from lightning? Or to protect a person who might be touching it?

First of let me state that surge protectors can be a little bit of a controversial issue,even amongst electronics geeks. That said, I can't believe that a home inspector actually told you not to worry about it. For a surge protector to actually work properly you NEED to have grounded outlets. In order for your surge protector to reroute power surges, it diverts them through the ground. Without a grounding wire your surge protector is nothing more then a pretty power strip. The 2-3 prong adapter will only make them fit and nothing more. This is why your surge protector manufacturer does not honor their warranty without using a grounded outlet.

You should also realize that just about no surge protector can protect your equipment from a direct lightning strike, which is extremely uncommon. For that you'd need a lightning arrestor. A surge protector is there to help divert voltage spikes caused by a variety of reasons, like major appliances turning on and off, but not lightning. Most of the surges that your surge protector stops probably won't actually "fry" your expensive electronic equipment, however it can decrease the lifespan of said equipment. I would recommend reading up some more on surge protection at the link I sited below. It should help clear things up. With electricity it is always a good idea to have something grounded! Just in case of lighting or if you happen to touch the wrong wire or another piece of metal. My new house was the same way it all had 2 prong outlets and I went around and rewired all of them with 3 prong outlets and then you don't have to fuss with adapters or extension cords An earthed ("grounded") outlet is to protect you in case of certain faults which can occur in electrical equipment.