flying from LAX. traveling on wednesday july 20th. continental flight at 12:15pm. does one need to be at the airport at 10am or is 11 am early enough?

Will you already have a boarding pass? If you don't have to check in at the desk, and can either self-check or curbside check your luggage, you should be okay for a domestic flight. This means you really are at the terminal (and I don't mean on the shuttle bus or in the parking lot). If you have to check in at the desk, then I would allow 2 hours.

I'd plan on 10:30-10:45 arrival time to allow for any traffic snarls, which can pop up out of nowhere in that area.
A better question would probably be "what time should I leave for the airport?" along with noting your departure location in the Los Angeles area.

We just hit a 45 minute wait at SFO, at around noon, to get thru security one day last week, and that was with no wait in a luggage check-in line which would have added another 15 or more minutes.

I was sure that something untoward was happening and so I discreetly inquired and the TSA person, said, "No, it's been like this for a couple of weeks now."

I know that this is *not* about LAX, but it is just a cautionary tale about what can happen...We go thru LAX often but usually on the red-eye which is not typical of the rest of the day. Breeze thru those in 10 min.

clarkgriswold is right, the other important question is "how much time should I allow to get to the airport".

If it looks like a holdup at security, usually there are people that will assist you in moving up if you are on a tight connection.

You are right, mlgb, that is usually true. However, last week at SFO, no one in authority was helping those with tight connections! Some passengers were letting others ahead if the time was tight.