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me personally i would go white for 4 different reasons:
1. Reflects light away more than black so doesn't get as hot in the car
2. Doesn't show fingerprints as much as black
3. Less common so better resale value
4. Accessories match since they are white as well for the ocd
100%
 
I'd suggest you wait until the iPhone 5 comes out in the meantime if you have an old phone sitting around use that, if you don't then buy a cheap phone that will get you by. If you really want an iPhone to hold you over I'd suggest buying an old 3G they aren't too expensive and would be good enough until the next iPhone comes out.

As far as the color, my personal preference is white, I'll probably end up getting that when I buy a new iPhone. But go with whichever color you like the best.
 
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