Cotomom's observations are the same as mine. Coming into LAX isn't that bad, but you never want to try to leave from there. In fact, based on advice from my flight attendent sister-in-law I haven't flown out of LAX since 9/11.
It is true that SNA is generally more expensive than LAX, but I've got a couple of flights booked right now where SNA is cheaper than LAX or ONT, so be sure to use the feature on the travel sites to check other nearby airports.
Until recently I used ONT a lot (especially flying out early in the morning), but have been having trouble finding good flight times or prices. Actually had out of state relatives come in and out of ONT to visit DL (even stayed near the airport), and reported that if you avoid the bad traffic (it's really bad WB in the AM and EB in the PM) it's not a bad drive (but it's definately farther than LAX, LB, or SNA).
Finally used LB a couple of times late last year (in and out of Texas on American) and it was terrific!