As already mentioned, SNA is the closest to DLR (and my favorite to fly into). I'd choose Long Beach and Ontario over LAX as well. LGB is closer to DLR; ONT is about the same distance as LAX. I've flown out of ONT before, but not LGB. I just prefer the smaller airports.
On our trip in November, we'll be flying into LGB and out of ONT.
Unless, Alaska is offering some killer web specials to LAX, DW and I try to avoid it on our SoCal journeys.