IF you're looking at a good surge arrestor, it provides protection from line to neutral, line to ground and neutral to ground. Without an equipment ground, you've given up 2/3 of the protection.
There is no substitute for a proper equipment ground, especially when dealing with electronics. tsolanto's advice is fine in most cases, but you wouldn't see me betting my computer or TV on a circuit that does not contain an equipment ground.
Few things are harder to put up with than the annoyance of a good example.