I really wanted to get Milo the vacuum that's shaped like a cow that Nikki recommended, but to avoid endless fighting I would have had to buy two of them. The other gifts have sharing capabilities built-in, which I prefer to buying two of the same thing.
The only unique things the boys have that are truly their own are their uglydolls that their grandparents gave them for Christmas. (Ox belongs to Huck and Wedgehead to Milo.) Everything else they just have to share.
I know parents who have different theories on this. If you're a parent of twins or kids close in age do you prefer to buy two identical gifts, two different gifts, or one gift to share?