J.F.
this is ours from our recent vaca:
(fyi - my twins are 7 months old)
Diapers and all that goes along with them (we use cloth so there's a lot)
Wipes
Diaper Cream
Bottles & Formula
Bottle Brush & Dish detergent
Cereal and other babyfoods
Bowls & spoons
Bibs & Burp cloths
The meds my daughter is on
First Aid kit - check for expirations and fullness of bottles before you go!
Sunscreen & Bug Spray
Few outfits per day for each child
Whatever they sleep in
Socks, Pants & Fleece jacket (if the other clothes are all warm weather clothes)
Plastic Bags for dirty things / garbage
Swim Diapers & Swim Suits
Sun hats
Swim & Bath Towels
Shampoo/Wash
Pack-N-Play & Netting
Monitor
Toys & Books
Blankets (& an old comforter - we used it to lay out on the floor so babies didn't spit up on the carpet in the nice cabin!)
And that's just for them!
The babies had one diaper bag, one food bag, one clothes bag, one toys bag and a pack-n-play! my husband and i shared a suitcase for clothes, toiletries and phone chargers, etc... and my 11yr old step-daughter had 3 bags - clothes, toiletries and fun-stuff (books, mp3 player, games, etc). Then a pair of sneakers, sandles and watershoes for each of us.
Funny how kids require so much STUFF :)
Have a fun vacation!