There is absolutely no better investment you can make than in your alliance. If you view it as a get-the-most / give-the-least proposition, you're going to lose out every time. OP is probably better off staying "None."
I, El Bruc of Zilchistan, hereby surrender. I have set my AA to "Legion POW," decommed all CM's and planes (I didn't have nukes). I will be able to reduce soldiers and decom tanks in 2 days according to the CN message.