Besides getting your tickets online, which will save some money and allow you to check out both parks (I kind of like IOA better), for one day, you would not be able to do much unless you also buy the Universal Express Pass for that day (or days) -- read all the fine print about that on their Web site. (It's only good for one ride on each listed attraction); price varies by season. You might want to go on another trip when you can plan 2-3 days when you also have a rental car (or when you can afford to stay in one of their hotels, which includes the Express Pass). Parking is additional (I think it was about $8.00 last Dec.); and it's a fair hike to the parks, esp if your kids are young. If your kids are older (tweens/teens) -- they will probably enjoy US/IOA more than little ones (Seuss Landing is cute for little ones). If you are going at one of the really low seasons, where crowds are comparatively light, you might enjoy a day there, but if you are going at a time that has any kind of extra draw (holidays, events, etc.), you are likely to be disappointed. There are several excellent attractions at each park, but it can be hard to get on them (we were there at one of the busiest times, and the wait even in the Pass line was sometimes kind of long). If you do decide to go, just be prepared about what to expect, be flexible, and you can enjoy at least some of it (people-watching is always fun). If you have younger kids, the Spiderman/Cat in the Hat character breakfast at Confisco's might be fun for them (Thing One and Thing Two also there), Sam I Am outside.
