I just wanted to add a review as there are no 2007 reviews yet - I have only test driven the Frontier 4x4 SE, but I absolutely loved it - enough to spend $40,000 on one. It's on it's way here from MN and I can't wait - the clutch was very forgiving (I am pretty rusty with the manual transmission) and you could hear the engine's power, but she purred like a kitten. There is little road noise even at high speeds... I love it.
The salesperson was great, not too pushy and gave us a great deal. The dealership is beautiful - all leather furniture, big screen TV in the service waiting area... complimentary water, coffee, pop, hot chocolate, newspapers... you name it they have it.
As for the truck, I love the way it looks, interior and exterior. I chose Storm Grey as a color, and the interior is "Steel Cloth" I chose a few add-ons (rubber floor mats, chrome pipe foot rails, etc) and they were all very well priced.
That's all I can say for now, but as a first time Nissan buyer I can already see the difference between them and GM. I will write a more detailed review when I get the truck.
If you're thinking of getting one, go for a test drive - you will love it. This truck drives like a car, but has all the power you need to haul.