i have two navaras, an 05 D22 and a 08 D40. personally i would try the nissan first as they are a great ute. you may be thinking im a bit biased here. far from it, when i was looking for a new ute last year i tried them all, and i mean all.
the new nissans drive like a car and feel more like a car. where as the rest still feel like trucks and go like trucks, especially in the diesel's. the toyotas rated high on the crappometre gauge for the test drive, while nice inside if you like plastic and drab looking interiors, there on road ability leaves alot to be desired.
the mitsubishi was only marginally better than the toyota, but basically the same.
the ford ranger was a surprise and was quite nice to drive, but the price was just too high for wat i wanted.
the holden rodeo drove like a commondore so its just apparent why you wouldnt want that.
so my advice for what you are wanting would be either of the D22 or D40 single cabs. you should be able to do a great deal for a new one, an ex demo, or second hand one pretty easily. and both will do the job without any hiccups. definately go out and test drive as many as you can and develop a good opinion on what you want from that.
you should get a winner, good luck with it