I've gotten into the habit of making extra of cassarole type meals and throwing them in the freezer in disposable dishes. That way, any time I hear of someone getting sick or having a baby I'm prepared
The dollar stores usually have a great selection of disposable dishes and containers.
The last time I delivered a meal it was for a vegetarian family so I made tofu/ricotta/veggie stuffed shells. They were a big hit! The lady stopped me at church a few weeks later and asked for the recipe. They are great for non-veggie families too because the tofu is so well masked, they never know if you don't tell them.
I know how important fiber is after baby so I always try to think about that when deciding on a dish. In oregon there is a local company called emerald valley kitchen that makes a really great 3 bean dip (and salsa too). I like to bring a tub of that with some of those thin triangle triscuits.
The last time I had a baby I had someone bring individual tv dinner style containers with enchiladas and rice and a big tub of chili. I loved it but it was such a PAIN to prepare because it was frozen. The chili took forever to thaw out. My suggestion is that if you bring a frozen meal you make sure it isn't one that needs to thaw for 6 hours before heating.