I would say a qualified "yes" to taking an infant to disney.
We took our son to disney when he was 2 months old. We were there the first week in december. We did not go into a park - basically went around to all the hotels and looked at the different christmas trees/lights and gingerbread houses. he loved it. I took so many pictures of his pie-eyed face staring up at the christmas trees.
We returned for a week when he was 4.5 months old. This time we went into Epcot for a bit. He really didn't care that much... I figured he was too young to enjoy the MK and the crowds just weren't worth it. He enjoyed the parades, the live musicians and the scenery. He spent a lot of time in the carrier/stroller/backpack on those trips and seemed to be very happy and content.
We took him again at 14 months and visited MK for the first time with him. (Not our first time.) The only thing we could ride really was the Carousel. he loved it... also LOVED the parades. Took him on the PeopleMover and that was a mistake because of the darkness when you go into Space Mountain. Take a flashlight or something if you take baby on that one to break the darkness. I probably wouldn't advise the park thing even at that age, unless you have an older child who would enjoy/appreciate it.
Went again at 16 months and rode other things (Peter pan, pooh, carousel, etc.) LOVED the characters... loved it all. Went to Animal Kingdom and he loved that too. Don't know why there was such a big difference between 14 and 16 months at MK, but there was. Huge.
Our second one is due in two months, and our next trip is planned for the first week in December... so it'll be interesting to have a 2 year old *and* an infant. We're going to do it, though. I'm sure we'll go in the MK since our 2 year old will enjoy. I'll have my parents with us, so they will help with the baby care and shielding me while I nurse the little one.
I've just learned that when you have itty bitty kids, it is much more fun for them to spend like an hour doing something basic (walking around Downtown Disney, looking at characters, just playing in the pool) than trying to break your back to try to "see it all" because the bottom line is that they just won't appreciate it, and it will end up stressing *them* (and you) out. I would say never turn down an opportunity to go to Disney, just know your limits when you do go. My thought was that we'd spend time in other places (like Epcot and MGM) at first because once they get "of age" it'll be only the MK for years.
Anyway - good luck and most of all, have fun!!!!