If you haven't decided yet, take a look at Silestone. It's a fabricated stone product. As a result it has some of the best features of Corian and Granite.
It's been popular in Europe and is just entering the US market (our colors are not so bright). Unfortunately, it's not widely available yet.
We've had it for 6 months and love it. I doesn't stain or melt. It can chip or scratch, but not very easily. You'll wear out a key without ever making a mark. I tested this out on the store sample (at home). I had to grind on the sample a with a searated knife to make a serious scratch (hey, they said I could do all this). The recomended way to remove dried on crud is with a razor blade scraped at a sharp angle.
This product is also used for comercial floors at international airports, etc.
Anyway, take a look at: http://www.silestoneusa.com/ http://www.silestone.com/
Btw, I'm not in any way associated with the product and we do have kids in the house (8 & 12).