TDI. The sportswagen's higher luggage capacity makes it more practical, and it is probably safer for ferrying a toddler. Another benefit is that DSG box, as someone already had mentioned. But since you also considered the RAV4, that should be on the top of your list given you live in the snow belt and need 4WD. Believe it or not, the RAV4 V6 is the most sporty in Toyota's lineup for now and is rated the top small SUV in a comparison test in the latest issue of C&D.
In the same price range as the RAV4 or for a little more is the VW Tiguan (ranked second in the above comparison). The popular VW 2.0L turbo 4 has been a staple in Audi/VW community with plenty of available tuning options, so I would look at it too if I can afford it. I believe it also is available as TDI, but I'm not sure. Keep in mind, though, that VW's reliability record is below average according to Consumer Reports.