A nice note sent to the CEO or President of the hospital about your great experience is always appreciated, especially if you remember names of the people who took good care of you. Sending to the CEO/President ensures it gets seen as it filters down through the ranks, because they usually send it to the dept manager to show to the department and staff who were mentioned, and to put a copy in the employees file.
If you want to send food, I agree with the poster above who said get something in bulk from Costco or Sams Club as opposed to a smaller, prettier arrangement. Costco used to have these awesome giant breakfast muffins in a bulk pack in several different flavors. And it's true, junk food will get eaten with no crumb left behind. Most nurses like their sugar and caffeine while working a 12 hour shift!
@FluffyChix Nurses won't usually take anything, especially something consumable, from a patient room. One reason is that nurses see the germiest patients at times, not saying you are one, lol, but eating something that came from a patient room would be a potential germfest. Another reason, it is prohibited to accept personal gifts in most places, and taking something from a patient room would be like accepting a personal gift or taking something from a patients personal belongings. Now send a bag of candy out to the nurses station for them to put in their break room (it's then "theirs" and not "yours") and it would likely not last the shift!