Basically a sporty SUV is a way for people who need a practical sports car to skip the practical but uncool station wagon. I don't necessarily like this trend, but if you want a sporty wagon the most choices are SUVs, leaving the Magnum, Mazda6, Subaru Legacy/Outback, BMW 3-Series (which is too small), and Mercedes E500 (may have left one or two out, doesn't matter).
The best sporty SUVs are those that don't compromise their practicality for sport. That's the major downside of the Infiniti FX: its sporty styling decreases its visibility and interior room.
My favorites would be the Subaru Forester XT, BMW x3, and Cadillac SRX.