well my 300 gig Seagate Barracuda is very quiet compared to my friends WD 250, i guess it depends what you class as quiet really.
But as i say my whole system is very quiet so obviously your going to hear the HDD abit but its right next to me so thats not hard.
But as i say my whole system is very quiet so obviously your going to hear the HDD abit but its right next to me so thats not hard.