Ashlie:
If you decide to bring your daughter, feel good about the fact that there will be PLENTY for her to do. From Toon Town and Fantasyland in Magic Kingdom to Playhouse Disney and the Muppets at Hollywood Studios, Disney offers a lot for every age.
On the surface, my answer to your question whether you should wait until your 2-year-old is old enough to remember is, yes. If she goes when she is, say, 4 or 5, she'll probably be tall enough to ride many of the rides and certainly (with pictures) have fond memories.
However, the question is could you and your husband use the memory-making experience? The flip side of whether or not there are things to do for her, is that there are many things for the three of you to do together and allow you, as parents, to remember those early years fondly. From Character Meals where she can meet Mickey and Minnie or Pooh and Tigger to seeing her face light up at the fireworks or simply eating an ice cream cone, there's much that can provide wonderful memories and an awesome bonding time with your husband.
The cost is similar to that of many other vacations (especially if you consider going during Disney's free dining with details
here). So, don't let this trip rule out a future trip when she gets out of preschool. There's so much to do—and at every age. If it's in your budget: GO!
Wishing y'all a magical vacation!
Whitney