Yes, there will be 3 of us, but you have to remember that the effective weight limit is closer to 9 lbs., esp. with rolling carryons; the weight of the bag itself counts, too. DS will need some entertainment on the flight, so there are toys and books that have to come. The last carryon will have some clothing in it, but the laptop weighs nearly 5 lbs, so we won't be able to put that much in with it, especially as the power converters are very heavy. Winter where we are going is cold, so appropriate clothing will be too bulky to easily fit within the size limits, even w/ compression bags.
Unlike US carriers, they don't give that "personal item" allowance, so my handbag (which normally weighs nearly 5 lbs. by itself, especially with 3 sets of coinage in it) has to fit inside a carryon. We also carry a few water bottles and snacks, because the FA's are never around to give you enough water on international flights, and you never know when you'll get stuck behind the passport control barrier with a hungry child. Then there's the duty-free to consider; I get lots of requests to bring liquor.
I am actually saving some weight with my PDA, as it has an MP3 player which will eliminate the CD's and player, and it will also carry all the addresses and directions, and a lot of maps. I even put games on it so that DS can use it as entertainment on the plane.
BTW, about the digital photos, I wanted to add that it is really not a good idea to only carry one media card; because if it goes bad your camera won't work. I use pricegrabber.com to find the best price on media, as purchasing it online is almost always cheaper than at an actual store.