Hi,
I got the same problem with a Dell Vostro 1500...
This problem is even worse under windows vista, constant "clicking noise" like every second...
With vista, i use a small utility called "notebook hadware control" which boots with the OS and acts quite like hdparm since you set up an option to 254.
With linux i launch the "sudo hdparm -B 254 /dev/sda" command after each boot.
Before installing Mint, i had a Kubuntu 7.10, and after extensive search, i found a topic somewhere to make the procedure automatic at system boot (+ some stuff to change in some configuration files), but i didn't bookmark the page & i can't remember the thing

(hit me for this)
This is kinda useless post but i just wanted to let you know that there is a solution somewhere

While searching for info about this, i kinda understood that this ain't no critical problem, but HDDs have a limited "head parking" cycle number (like 600,000 or so), so this might shorten the HDD's lifetime...
Next, week, i'm in holidays for two weeks, so i'm considering calling dell for them to come fix this (since i have a j+1 1-year long guarantee, laptop bought in january)...
I just hope the dell guy will be able to ghost my disk or something since i just formatted the whole thing less than a month ago and reinstalled everything (and, believe me, installing vista, drivers, and apps takes almost forever...)
The "good" thing is that i now keep track of every "hack" i make on linux in text files so that i can find them back if ever i had to reinstall it completely...
Let the first who finds back the post i'm talking about post it here... thanx for that

good luck
ed