Books, dvd's for in your laptop, maybe even cd's for in your laptop, Ipod.
Comfortable clothing, but I never have pj's or something like that on during the day. Always just wear my clothes. But maybe also pack a pair or jeans that also fits comfortably when sitting on your bed or something.
I never really understand why someone would wear a hospital gown either.. Only time I ever wore that was for surgery but would be in my own clothes the same day. Only time I wore one for longer was post transplant.
Also, ask if you can have all your own meds in your room and take them on your own time. I really don't like it when I have to wait for my meds. Not only enzymes, but all meds. Also maybe your own nebulizer. Ever since I have my Eflow I always take that with me, as it is so much faster!