Do you want brand spankin new, or do you want slightly used with good warranty (certified used)? Do you have a lot to haul around? If given the chance and the capability would you go more off roading than just a drive in the snow? And how big do you want? These are questions ya gotta figure out first.
Personally, i say limit it to the Nissan and Jeep. I dont like the ford design, and find it uncomfortable inside and out, same with Toyota.
With the Nissan SE supercharged V6, your looking at a *slightly* larger car. They are virtually identical in size, weight, and power, with the jeep getting better fuel mileage, plus no supercharger to die. The Jeep has more ( much) passenger space, but less cargo room, and waay better rear leg room. Its not quite as long and a little wider.
Check out this site for some side-to-side comparisons of the cars. Its most excellent for getting an idea of the differences.
http://autos.msn.com/compare/choose....=10529&pt=dual
In the end it comes down to personal preference. go out and Test Drive them all before deciding. Again, i reccomend certified used cars though.
Im also a Jeep guy though, with nothing but the best, most reliable of luck, so im slightly biased.