Personally, if you can afford it, I would pick up two: either an Ultimate and Absolute or an Ultimate and Zone Classic. The Ultimate is a must, as it can serve as your heavy oil ball. The Absolute or Zone Classic will give you a bit more push then your Smash/R but will recover harder. I have both, and they are both awesome. For me, the ZC pushes about 5-6 feet further down the lane and recovers harder and with more snap. The Absolute starts up just a bit sooner and delivers a smooth, hard arc on the back. Both are great balls. Which one you choose will just depend on the look you want. Good luck and good bowling to you.
P.S. Be careful with the Ultimate. It's an extremely aggressive ball. You'll most likely have to put a good amount of polish on it unless you have very high ball speed or only intend to use it on floods. It's that strong. It's a great ball, though, one of the hardest hitting that I have in the bag.
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I can't bowl 300, but I can bench 340 : )