I've seen a 3.5" external hard disk at Challenger
Tampines.
$249 for 250GB. $189 for 200GB. Good prices, I must say. If you're
not going to be lugging your external hard disk around, and you
need lots of hard disk space then I suggest going for this.
I don't need so much, though. I bought a 2.5" 40GB external hard
disk for $129 at Sim Lim. I just need it for backing up of some
important files, that's all.
By the way, just remember to use the 'Safely Remove Hardware'
function before unplugging the hard disk from the USB port, and
it'll be fine.