I'd like to take a breif moment of your time to be theis blog's resident Dalek nerd and clear up a few things (Thomas, pay attention!)
"What on earth is the need for all those hemispheres on their metal plate body?"
The hemispherical globes on the lower part of a dalek's casing replace the external sense organs of a dalek that are not already catered for (such as the sense of smell).
So, basically, the globes are there so they can smell you, and presumably taste you...if they so desire.
"No matter how many times you kill the species, one always manages to survive and create a billion more."
Erm, hello. Cybermen, anyone?
Now, as to Dalek's being scary, let's think about this for a second. Sure, I'll agree they're not all that scary to look at. But let's all put on our empathy caps for a second. If you were faced with a genocidal lump of nigh on indestructible metal, I'm pretty sure you'd be peeing yourself. You can't reason with daleks, they have no emotions or sense of mercy that you can appeal to, and they will kill you as soon as look at you. Because you are not a Dalek. Almost any other villian or monster in the series can be reasoned with or delayed or hurt to some extent, but it's almost impossible to do any fo these things to a dalek.
And let's also remember that when we encounter th daleks it the show, most of the time they are in very small numbers, with only themselves for weapons. But when the time lords fought/are fighting/will fight (I hate time travel...) the daleks, they are in vast numbers with a formiddable arsenal of pretty damn terrifying weapons. There are special weapons daleks, dalek battle ships (for example, the Dalek cleaver, able to hurl itself through mountain-sized objects withouteven losing speed, or the Skaro Screamer, cabaple of turning the atmosphere of a planet into liquid oxygen for fuel.)
So yeah, Tom. I'd say the daleks are actually pretty goshdarned scary :L
Dalek Survival Guide, published by the BBC. This book could save your life.
Anytng by Terry Nation (creator of the Daleks)