I'm assuming that my post below spurred this question, so I'll tell you why we choose to take our child on cruises with us. Our little man went on his first cruise (our 6th) when he was 9 months old--5 days out of Charleston, which is only two hours from our home. Our next cruise will be out of San Juan (he will have his second birthday on the ship), and we have already booked another for Bermuda next May.
Grandma and Grandpa usually cruise with us. They live several hours away, so cruising is the perfect time for all of us to connect for a carefree time of fun and togetherness. For us, a cruise is a FAMILY vacation, and he is part of our family. My husband and I recently DID leave him with the grandparents for a romantic getaway (3 days), and it was great. However, 7-9 days away from him would NOT be great. We're not going to take a week off work just to spend it away from the little guy who is the light of our lives.
I will say that we enjoyed every second of that cruise and having him there was never a burden on any of us. Was it different? Absolutely. I had to pack a lot more things, and we had to consider his schedule when making our own. But different is not always a bad thing. We are not big partiers and Grandpa doesn't enjoy the nighttime shows anyway, so we were able to participate in all of the activities that we would have if he hadn't been there. I can assure you that there was no shortage of romantic moments...infants go to sleep very early. ;-) Babies are not lumps of clay. Part of the fun of cruising with our new family member was seeing him respond to the lights, sounds, and people that he met on the cruise. The crew was absolutely smitten with him, as they rarely have an opportunity to see babies because of their jobs.
Why not choose Disney? I'm sure that we will go on a Disney cruise some day, but I don't WANT to cruise Disney right now. We have already been everywhere that they go several times, and we choose our cruises mostly for the ports rather than the ship itself.
I can assure you that we recognize that our child should not impose on the fun of other people, just as I expect other people not to impose on our right to enjoy our cruise. If he fusses, one of us will take him out until he calms down. He does not (and will not) run about wildly or unsupervised. Even at this early age, our child is learning to respect others and to use manners as well as a toddler can. My mom always says, "Your job as a parent is not to rear a child that you can love; it's to rear a child that other people can love too."
So, (thunk) down off my soapbox.

I think I'll go work on my packing list. After all, only 16 weeks to go! I have a lot to pack, as you might imagine.