if it stays at those temps after an hour or so thats really good, it looks like you had only been testing for 7-8 minutes at this point, its generally better to let it run for a while so you get a good judge of your max temp over time and stability of the system
Temps look OK sofar (I'd probably NOT say Great), However:
NOTE: Great would be upto 20C > than ambient ie mid to low 50s
1) Do need to run a little longer. I find that Prime95 (blend mode) will reach close to max within 10->15 min.
2) Prime 95 will heat the cores up more than the vast majority of Games, so gaming should result in lower temps.
3) You have a "K" CPU, so I'm guessing you are planning on OCing. This will increase temps and depending on if you have to increase Vcore it could result in an increase as much as 10->15 C.
4) You should run Prime95 for at least 4 Hours to Check Stability, espeacially with Overclocking and that will also show what max temps would be. Need to watch closely for first 15 Min. If not above 70 C should be good but if hitting higher then need to monitor untill you see it stablize.
Your CPU is good upto 80->85C for a short period - Throttling starts at around 100C and if the decrease in speed does not stabize temps then shutdown happens around 125C.
Point of reference, I have a i5-2500K OCed to 4.2 GHz (good upto 4.8, but just not that big of difference from 4.2->4.8). The i-2500K does run cooler than SB CPU so have to take that into account, But my temps:
58->62 C, prime 95 after 30 min. Have the Zalman 9900Max HSF (Somewhat expensive but I like it).
My prefered method for HSFs that have "valley" along the heat pipes on the Base is to use a credit card and completely fill the valleys (none on the "flat surface"), then use the "x", or Place a small amount on the Top of the CPU and spead VERY thin using my finger (latex glove).