Hard drive parking heads excessively

I recently installed a new Seagate Momentus 120 GB 5400 RPM hard drive in my Mac mini. After installation of everything, I've been noticing that the heads are parking rather frequently when the system is idle, about once every 10 seconds or so. I know that's not good for the drive, as they're usually rated for between 300,000 and 600,000 parks in their lifetime. Googling the subject brought up a whole bunch of other people with different brands of different drives having the same exact problem.

I've tried using hdapm to set the APM settings to max, but that doesn't work for me for some reason. It tells me that my drive doesn't have APM features, which seems odd to me considering that it's a new laptop drive. I've also tried using declunk, an application that writes to the drive to keep it from idling and parking the heads repeatedly. That hasn't worked for me either, as it continues to make the same little tick sound every 10 seconds or so. I'm really stumped on what to do next. Does anyone have any other ideas about how I might be able to remedy this? Are there any brands of hard drive immune to this problem?

And just to be specific, my Mac Mini is the original 1.25 Ghz Power PC model, and the hard drive model is ST9120822A, if that helps any.