They are crane flies (mostly species of Tipula).

They're beneficial in the sense that their larvae feed on decomposing vegetation in mucky wet areas.

A couple of fun myths: many people call them "mosquito hawks" or "mosquito eaters", thinking they catch mosquitos. And an old Italian myth: they poke you in the eyes (and why else would they have such long legs?!).

Joe

Cal: I live in OC too. Those crane flies are completely harmless, but they drive my wife insane. Luckily I have a solution: carnivorous plants. Here's a photo of a sundew feasting on an unlucky crane fly:

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Thanks I always thought that was what they were like many others. We don't get bothered by them and aways left them alone. Nice to know what they really are
Paul