I actually like wagons. Seriously considered a BMW 323 Sportwagon (5-speed manual) before I got an IS. I think most people have an aversion to wagons -- sitting in the back seat on hot summer days, literally being dragged by parents on road trips to nowhere, fighting with siblings, yelling, etc. And those wagons I'm sure didn't handle as well, (can you say psychosteer?) either.
However, the wagons I like (European kind) handle just as well as their sedan siblings, and provide some utility. It's too bad IS wagon only comes in automatic... oh, well.
I'll probably trade in my current IS for the 5-speed manual, and look into a wagon (Matrix, maybe) to replace my Celica.