Congratulations on the soon-to-be-here-baby!
Ok, first let me say that there is such a thing as OVER packing for the hospital; I did it, so I know!
There are the basic things you'll need - the "going home outfit' for the baby, going home outfit for Mommy (I gave birth in June, so I had on a pair of cotton, elastic band shorts and a tank top - my point is, you want something comfortable and roomy), your toiletries (depending on how long you'll be staying in the hospital, you'll still want to shower with YOUR shampoos and soaps and lotions, your toothbrush, hair stuff, etc), camera and plenty of film (or batteries/memory cards if it's digital), a notebook or journal (to write down visitors, gifts received and just your thoughts and feelings during the whole labor and delivery process as well as after - I did and transcribed it into my son's baby book), any necessary insurance/doctor paperwork INCLUDING your birth plan (if you don't have one yet, you can look up "birth plan" online and get several good websites/ideas for one), comfy slippers for you, old undies you don't care about (several pairs - trust me on this), change (for the pay phone) or even pre-paid phone cards (for those all important first phone calls), a radio (bring batteries just in case - I wanted music while I was in labor), if the hospital has a VCR in your room (or better yet a DVD player) bring some videos/dvds to while away the labor time (or for even after delivery - remember, this will be your last chance for some "down" time for a while!!), and of course, don't forget the car seat!
Here are some things that I packed that I didn't use:
-crossword puzzles and my latest Kinley McGregor novel (with all the people in and out of the room, I never could finish that paragraph);
-nightgowns/PJs - it was just easier to wear the johnny that they gave me, plus, if it got "stuff" on it, I didn't care (and you will get "stuff" on your pj's)
-3 changes of clothes - what was I thinking??!! I lived in their hospital gown for 2 days; I got undressed at 10am on a Tuesday and didn't get dressed again unitl 4pm on a Thurs!
-my pillow from home - again, I decided I'd rather "mess up" the hospitals linens, bedsheets, pillows etc, rather than ruining mine
-diapers for my son - the hospital loaded us up with diapers, formula, wipes, nuks (pacifiers), baby soap, baby shampoo, baby lotion, etc. (word to the wise, have Dad bring the nursing station coffee in the mornings when he comes to visit you - they LOOOOVE that!)
-my birthing ball - the hospital had one that I could use (although, I would double check this in advance)
-deck of cards - yeah, I was an uber dork and thought we'd get to play some Spades...HAHAHAHAHAHA!
-my address/phone book - everyone called ME. I never got a chance to call anyone.
And that's about all that I can remember from my experience. I ended up packing waaaay more stuff than I actually needed and of course, you always go home loaded with goodies and presents (from the hospital, the doctors and of course, family and friends).
Congratulations and best of luck!!