Your motherboard and CPU are no doubt excellent. If you plan to overclock the CPU, you really have to buy an aftermarket CPU cooler. I'm using i5 2500K CPU, Cooler Master 212 hyper plus cpu cooler and Biostar TZ68A+RCH motherboard. I easily overclocked the CPU at 4.7 GHZ, very stable not even go over 63 degress fahrenheit at full load, in idle the temp is from 36-39 degrees Fahrenheit. Run Prime95 for 12 hrs and very stable. BTW, the PC case is CM HAF 932 advance edition. lot of fans very cool.
It's less about what speed, and more about voltage. Set a reasonable voltage goal for longevity, and then see how much speed you can get out of it. Start with its default voltage and see how high you can get the multiplier before encountering stability issues. For my i7-2600k, my personal preference was to not exceed 1.38V for 24/7 use. After tweaking, I found I can achieve a speed of 4.6ghz at 1.33-1.34v, and then its kind of like dropping off a sea shelf from there requiring more and more voltage for small speed gains, so I stuck with that as its an excellent overclock at a pretty decent voltage. YMMV based on temps, air circulation, voltage regulation, etc.