Currently I consider Samsung HD204UI as best buy. I heard that it doesent have head parking issue, and its about $15 cheaper than WD20EARS. Unfortunelly, according to reviews it is 1~2 dB louder than WD20EARS. What do you personally think, should I go with the Samsung?
Alas I can't really provide a definitive answer to that question. I have six WD20EARS in my media server/HTPC and I've been really quite impressed by them - they're hard-mounted in a PC-Q08, and there's not really any sign of vibrational noise. There's a soft whoosh from the drives and the rest of the system, but it's easily lost in domestic noise.
I have used the Samsungs too, but not in a quiet environment, so I can't really compare. Seagate - no idea, not used a Seagate drive in years in my quiet builds, since they lost their crown here as the silence champ.