The board size doesnt matter. Any cooler will fit. What matters is the case you choose. Different cases can accommodate different size coolers. If you want to push the 2600 to around 4ghz or above, you will need one of the big juicy tower coolers like the Noctua NH-D14/D15/s, Cryorig R1, BeQuiet Dark Rock, etc.
And for those big coolers, you will need a mid tower or full tower case, depending on which one you choose.