If money isn't a problem, I would say spend both days at Disney/CA and get park hopper tickets as well.
My experience with families has been if you are only spending one day at a park, there is a lot pressure to run around and do things as fast as you can. You can't relax and physically it can be quite exhausting which might not be a problem on day 1, but day 2 you will really start to feel it.
By getting park hopper passes both days, it gives you plenty of time to see both parks, revisit favorite rides and, for lack of a better term, just to stop and smell the roses. Plus, it minimizes driving. Also, with the extra time, eating outside of the parks becomes an option so you won't be stuck with park food.
There is a mall next to the parks called Downtown Disney, you may want to check that out for shopping and restaurants.
-KeithP
If you really want to hit up Universal, I disagree that it is boring, get park hopper tickets for 1 day and hit Universal the next. To avoid traffic, hit the road early in the morning and eat breakfast somewhere near Universal Studios.