fosse76 - themed queues aside, did you catch any shows/parades? DCA has Pixar Play Parade and the Aladdin musical.. in addition to other streetmosphere shows. Sounds like you skipped a lot if you only spent half a day there. There's also World of Color coming up next month, which will keep many guests in the park until dark.
I hate parades. ALL parades. I find them pointless so I skipped them. I saw the Aladdin Musical twice (and must say I find their preferred seating policy extremely discriminatory, especially considering how it is a "locals" park). The few times I walked down Main Street, I didn't see any streetmosphere performers. I spent quite a deal of time in the Main Street shops (including the gallery next to Lincoln, with the Peter Pan painting I desparately want to own), watched a few cartoons at the Cinema, meandered through New Orleans Square, watched the quartet as it was conducted by Mickey Mouse; a few days later I caught a band in the Square, took the Omnibus, spent some time people watching near the statue in the hub. I spent very little time actually waiting in any lines. I took hundreds of pictures. So I can say I didn't skip much of anything.
As for the OP's question - My thoughts on this are simple.. You can never go wrong with Walt's original Magic KingdomI think every Disney fan should try and visit Disneyland at some point in their life.
I like Disneyland better. It just feels like there's more to do in a closer space. I was lucky, crowds were pretty light. Even Saturday, my last day there, was a bit slower than I expected (but it was definitely more crowded). What I had is the advantage of single-rider lines + good timing. A lot of attractions in any theme park tend to have differing periods of busy-ness. I just happened to get to a few of them during a slow period.