I'm not quite sure what everyone's replies mean to be honest. The 12" Powerbook I owned previously to this one made a rather loud "clunk" sound that sounded like a marble dropping. I recall it was an issue many people over at the official Apple forum were concerned with. It too was a Seagate drive.
I reported it to Seagate with a recording of the sound, they in turn informed me it had something to do with a motion sensor built into the hard drive. I lived with it for the time I owned the Powerbook. When it made the sound the Powerbook would freeze momentarily for maybe a second.
I thought maybe this might be the same kind of thing going on, except the sound is much quieter and is a definitive "tick" sound and my Macbook doesn't freeze at all. However upon investigation over at the Apple forum other people who have this sound do not all have the same brand hard drive (Fujitsu for instance).
Now I am not being a perfectionist in this regard, the sound only started to appear within the past week. I ask the question because I am legitimately interested to know if other people are experiencing the same thing and whether it may be something to be concerned about. Alright perhaps I was a bit dramatic in my opening post and I apologise for that.
The odd thing is if I am actually doing something on my Macbook the sound doesn't happen (like now as I type this post... no "tick" sound), but if I'm just surfing the net or reading through posts on this forum for example the "tick" sound (which is quite definite) will happen maybe every 10 or 20 seconds.
I merely would like to know if anyone else may have this on their Macbooks and perhaps what some people think it could be. Perhaps I should have said that at the beginning. I didn't want rhetoric, just intelligent opinions as to what some people who may have this sound think it could be.
In any case I'll take it into an Apple service provider and get them to check it out, although I am not keen on letting them open it up if it can be avoided.
EDIT: One idea I have is when I had the 60GB hdd this sound wasn't present, I changed it for a 100GB hdd of the same brand/model and the sound appeared. Now I think (and I may be way off) perhaps because there is that much more room on the hdd to read the Sudden Motion Sensor software Apple is using is causing the hdd to park more often when it is not being fully utilised. What do you think?