Clicky could be the HDD, buzzy could be the fans or the HDD while it is spinning at slow speed.
You can use iStat (www.islayer.com) to see how fast your fans spin, and if it in any way correlates to the noise you hear.
The clicking, if it is from the HDD, might occur during sudden movements, or may be a sign of some imminent failure.
Have a look at SMART Reporter to see if the SMART Test shows any failure.