How big are your kids? This makes a difference when you are considering a double stroller.
We have two boys, 2.5 and 1 right now. We take them to
Disneyland VERY often.
We have too many strollers to count.
Right off the bat, rule out the front to back tandems and the sit 'n' stands. Neither are easy to maneuver OR light enough to carry effortlessly.
When we go to DL, we always take the Combi Twin Sport. It is a GREAT stroller. It can hold 90lbs of kid, and it is very lightweight itself (I want to say 14lbs). The seats are nicely padded and recline fully. The baskets (2 of them) are big enough for blankets, sippy cups, toys, sweatshirts, etc. It has a cool "tri-fold" mechanism, so it folds up about the size and shape of a golf bag. In addition, it has a shoulder strap for carrying. It is only 29" wide and fits through standard sized doors. It is easy to steer, but you do need to use two hands when the stroller is fully loaded. If there is only one child in it, you can steer one handed. The front napper bars remove individually, so if your older one doesn't want one you can take it off (also makes it easier to get in/out). It has 5 point harnesses, but they can convert to 3 point by unclipping the shoulder straps. The fabric of the seats wipes clean and is water resistant. You can easily cover the whole stroller with an adult sized poncho, but they do sell a rain cover for the Combi. The Combi Twin Sport is $200 at Babies R Us. Don't bother upgrading to the Twin Saavy...the extra features are not worth the money (basically, you get cupholders and a parent organizer for almost $100 more on the price tag).
I think this is a great double stroller for theme parks. HOWEVER, one caveat is that the seats are a bit narrow (not a problem, as my boys are not "wide", they are pretty slim). This is so that the stroller can fit into doorways. The Maclaren twin strollers have a wider profile, and they do not fit through doors as easily, although they claim it does. I "test drove" both the Maclaren Rally Twin and the Combi at the store and felt the Combi had more going for it for the money.
We have a single Maclaren Quest that I am in love with.

Steers like a dream, and I use it when I have both kids grocery shopping. Put oldest in the cart, youngest in the stroller and I can pull cart/push stroller each with one hand.
I also have a Chicco Capri umbrella that is great too, but it does NOT steer one handed, thus the need to buy the Maclaren.
If you do end up taking two individual strollers, the Chicco Capri is a great one for older kids, since it doesn't recline much at all! It is only around $50 and has that handy carry strap. My 2.5 year old likes that stroller very much. It has a 40lb weight limit, but is better for shorter kids, since the sunshade and seat back are pretty low.
For a younger toddler, the Maclaren Quest is pricey, but it is very well appointed. It reclines fully, has an extendable legrest, great sunshade with tilt feature, one handed steer, carrying handle, storage pouch on back of hood, and pretty decent basket underneath. It also has a higher upper weight limit and can accommodate a taller child.
Our stroller situation is a bit unique, since our older son is very small for his age. He is super skinny (27lbs) and average height (36 inches). His little brother, however, is already 25 lbs and 33 inches tall. They are 20 months apart, but the youngest is FAST approaching the oldest, and they are looking more and more like twins, thus these twin side by side strollers work out well for us. We know that our oldest son will be under 45 lbs for a LONG time.
