DISNEYLAND! 
Not as often as I would like, though, as it is more than three times further away than WDW, and I don't fly. I'm planning a long-awaited return trip to Cali for 2012 or 2013 that will include Disneyland, DCA, Knott's Berry Farm, Magic Mountain, Sea World San Diego, San Diego Zoo, San Diego Wild Animal Park, and then up to the Bay area for Walt Disney Family Museum, Great America, Marine World, Bonfante Gardens, Santa Cruz Beach Boardwalk, and maybe some of the other zoos and national parks in the state, depending on how much time I have.
Theme parks are my biggest passion in life, and Disney are my favorite parks for the theming, atmosphere, characters, songs, stories, and all-around happy vibe. But I also love roller-coasters, and enjoy the large "regional theme parks" that sprang up in the major metropolitan areas around the US in the 70's and 80's; and traditional "mom and pop" parks. So, ALL of my trips are planned around visiting theme/amusement parks. Since I also love animals and zoos, I also hit some of the zoos and animal attractions that are in the area of the parks I visit.
For instance, if I go to Busch Gardens Williamsburg and nearby Kings Dominion, and then up to Hersheypark and/or Great Adventure, I'll also hit the National Zoo or another one/s in the area. When I visit Dollywood I do the Knoxville Zoo and some hiking in the Smokies, and if I go home through Chattanooga I like to check out things like The Lost Sea, Rock City Gardens (especially during their Christmas light display), etc. A trip to Six Flags parks in cities like Atlanta, St Louis, Chicago, Dallas, and San Antonio will also include the zoos and various attractions in those respective cities. (And in the case of San Antonio, Sea World, which, like BG Williamsburg and Sea World San Diego, is free on my Busch Gardens/Sea World Florida Platinum Pass!) Metropolitan zoos are easy to include on my trips even though I tend to travel at the times when the regional theme/amusement parks are open weekends only, because the zoos are generally open almost 365 days year round.
To date, I've now visited 54 theme/amusement parks, approximately 30 zoos/aquariums, about 7 National parks, various nature trails and hiking areas, and several tourist attractions that don't fit any of these categories. Most of these are in the southeast, northeast, midwest, and east Texas, as I can generally get to any location in these regions in just a one day drive. (unlike Cali, which takes three days or two very LONG ones!
I've "only" been to 12 waterparks though (7 of which are in Florida), since I like to travel in the fall, winter, or early spring to avoid the heat, and most waterparks are seasonal and are closed when I am near them. The Fall months in particular are a favorite time to travel throughout the country, because I enjoy the fall foliage, cool temps, and the fact that the regional parks have really late hours in October for night rides on the coasters. This is because they do night-oriented Halloween events which, ironically, I have zero interest in, other than the fact that they offer late hours on cool October evenings.
Christmas events, however, are another story, as that is my favorite holiday and I really get into the Spirit of the Season. I enjoy my annual stint at WDW beginning around December 28 ( in time to see all the decorations, Christmas entertainment, and music loops, and it's all FREE with your AP at the MK during this time and not an after-hours upcharge
, Besides WDW, my favorite theme park Christmas events are the ones at Dollywood and its sister park Silver Dollar City, which thankfully begin in early November so I can visit before Thanksgiving. These charming mountain parks are transformed into a Winter Wonderland of lights and have excellent Christmas entertainment, and all rides are open except the water rides! These award winning (Amusement Today's Golden Ticket) Christmas events are highly recommended.
