I wish my two passports were a privilege [although I know what you mean]
The one on the left is my current valid Serbian passport [and not many privileges come with that - although I didn't need visa for Cuba and Belarus on my recent trips ] that has replaced passport on the left - cancelled Yugoslav one. But, as I still have valid UK residence and US visa in it [and it's quite costly to transfer them to the new passport], I have to carry that one as well.
What a coincidence, my 2nd passport is Serbian as well. Besides the new red passport looking cool, there is not much convenience. I will be travelling in the Balkans/EU this summer so I need to have both with me.
On another note, what about a decent wallet here in the US that fits the UK large bills? My US CK gets the edges of the bills all messed up becasue the UK pounds don't fit well in it. My friend that is now in China and HK also has a problem with that.