I guess it needs to be said one more time (at least).
A 2X4 is a piece of wood or metal. A 4X2 is probably a vehicle.
The first number is for the number of wheels on the ground (duals count as one wheel).
The second number is the number of wheels that CAN be powered (again, duals count as one wheel.
Thus, a 2X4 would be a 2 wheeled vehicle with 4 driving wheels. Pretty unlikely!
A 6X4 would be a three axle rig with two driving axles. A 4X6 would be, again, pretty unlikely.
As for what YOU should buy, most assuredly it should be what YOU want or need.
I bought a 4X4 because:
1. The price was right, for a diesel 2500.
2. It is towable behind the motorhome, should I decide to do so, without modification.
3. Around here, 4X2 trucks are as rare as 4X4s were when I was a teenager.