It's a good idea to check the alignment, whatever your choice of camber may be, when you put new tires on. What you don't want to do is put new tires on an alignment that is even slightly off and wear those tires even more prematurely than the negative camber as the effects of negaitive camber are multiplied by a slightly off caster.

Regarding the negative camber, I chose to straighten up the rears to get more life out of the tires like nom3rcy said. Safety to me is a bigger picture than just less than 1 degree of camber . . . I don't drive like a maniac, I drive safely which is what I think has more to do with safety. Also, regarding the handling . . . again, a less than 1 degree camber difference is not going to make the difference between your X handling like a Ferrari or a Suburban. But there is an excellent chance that your expensive tires will last longer on the straighter setting. My camber is -1.7, minimum spec is -2.0 . . . 3/10s of a degree difference.

I'm not trying to convince anyone to straighten their camber, make your own decision. I made my decison after my 3rd set of rears in 45K miles. Also, I need to save my money on tires so I have enough to make repairs on everything else that breaks on the X . . . which is . . . everything else.

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2010 Lexus RX350 still new
2003 BMW X5 3.0i w/sport package w/68K miles. (gone Thank God!)
2002 Dodge Ram 2500 4X4 cummins diesel w/198K miles, custom repo truck
2009 Scion tC w/46K miles
2007 Suzuki SV650 custom streetfighter
2000 Lexus GS400 w/165K miles