RC, imo...i think you can't go wrong with black. Its a classic color, with a long life, (as you said your keeping yours for 5yrs) Friends of mine, as well as myself, have always wanted that LOUD color, and then you go ahead and get it. Its great for the first few months, and you love just how loud, or how well it complements the specific car. But alas, after a while, the color starts to wear on your eyes, and you wondered why ever in the first place you choose something so, well...red. Or yellow for example. On one of my first carreras, I got it in speed yellow, and for me, when i took delivery, I was just ecstatic.
But down the road, it really started to get to me. It just had too much attention, and I really "grew-out" off the color. When i got rid of it and bought my black/black 996tt, I just couldn't of been happier, and everytime i look at it, I just fall in love with it again and again. I think the only other color id get would be cobablt blue, but in my personal opinon, over the whole life of the car (5 yrs?) you won't be happier with anything other than black.
P.S. Your "first instinct" was also to order black wasn't it? I think you really have to trust your gut, and go with what you set out to get.
Regardless - this car will look good in pink even, soooo theres really no way to lose here.