On my 500 mile drive home from the $tealership (possibly the worst thing one can do is exactly that - I made sure I took more stops than usual and nver went over 65 MPH) I made a very conscious effort to vary my speed - my apologies to anybody who was behind me that day from Buffalo to Long Island. As others have said, it is good for both ring sealing and for pulling oil up to the top of the motor.

I changed the oil at 500 miles, 1000 miles, 2000 miles, and again a 3000 miles, with routine 3K intervals after that. I used the Nissan OE filter and the a name brand 5W-30 oil, per the manual. At the next oil change (9K) I plan on switching to synthetic (most likely Mobil 1) and maintaining the 3K interval.

One can never hurt a car by over-maintaining it - with that kind of treatment my last Nissan truck went over 350K before it finally rotted away.