We just traded our '07 X3 for an X1 xD28i.
The X1 is a good bit smaller in many dimensions, so I would characterize it as a "high wagon" (more like an Audi Allroad).
That being said, the capacities and dimensions people are quoting (I have not looked these up myself) seem to indicate it actually has less cargo space than the upcoming 3 series Touring, along with many competitors' wagons. Is it "enough?" Well, that depends on your needs. It has good driving dynamics for what it is, but it seems that if you want still better cargo capacity and (perhaps) still better driving dynamics, the Touring might be the ticket.
The X1 is a cool vehicle, and it exists only because Americans will not buy wagons, and the rest of the world won't buy (ie wants better economy than) a typical "SUV."
It was the perfect vehicle for us, because, alas, my wife would not consider a "wagon" (though I would gladly) and we wanted better economy than the X3. Bingo - the X1.
Hope this helps.