I just flew Delta at 6:30 a.m. from Providence to Atlanta, and we were served a cup of yogurt (peach going down, strawberry coming back), a danish, a banana, and orange juice. You could also get coffee, milk, soda, etc. if you wanted.
Since I am not a big breakfast person, this was perfect. In fact, I ended up saving my banana for later! DD and I are headed to WDW next month on a 3 p.m. flight. Probably will only get the peanuts/pretzels on that one.
On past lunch time flights with Delta, I've had ham or turkey sandwhiches, with a brownie or cookie, and crackers with cheese. I really don't have complaints about the amount or quality of the food. Very decent for the airlines!
P.S. I always fly coach, so I have no idea what the first class are served. I would assume they get more than yogurt!