We like August -- it just fits in our schedule. This year we're doing HHI, though, for a change of pace!
As for WDW in August -- expect HEAT, and HUMIDITY (but boy those pools feel great!) Crowds aren't too bad -- we've surely seen worse in the summer, xmas, and even October. The later you go in Aug, the fewer crowds, but also a greater risk of shorter park hours or a booked event -- that would stink.
It rains a bit every day (late afternoon downpour for about 30 mins -- enough to clear the air!) So take your poncho or take a shower -- whatever!
We had a hurricane while we were there last year (Charley). In our case, it really wasn't a biggie -- I'm sure, however, the Cms and fellow Floridians would GREATLY disagree. WDW does an awesome job of building its facilities; we felt VERY safe in our BWV investment after it withstood Charley the way it did! Didn't even have so much as 5 seconds of lost power. We made pancakes, watched Disney movies and let the storm blow over. The next day, nearly all the parks were back up and running -- how they manage that, well, it's just amazing. You really feel for the Floridians, though -- here you are, having a grand ol' time, and then find out the same person who's smiling and serving your dinner has been without a home for the past 2 days, basically living at Disney!