I almost always use the stock coolers since I buy box processors (for the fan and the extra warranty). I don't typically overclock, and the stock cooler is designed to handle the thermal requirements of the CPU. The one time I felt I needed to get a improved cooler was my Q6600. It was getting in the 70s while running Prime95. It was a little too hot for my tastes. One of the designs where heat pipes draw the heat up into an array of fins worked well for me... with a price under $25 (after rebate).
I'd say go for it with the stock cooler... if temps are too hot, then consider finding an affordable cooling solution.