I don't know too much about Toshiba PC's but ill be honest, whenever you know what brands are good, you don't tend to go to something you don't know.
And again different types of brands tend to be used for different types of things.
About alienware, narg summed it up pretty well, but to give more details, alienware reminds me much of
Icrap products.
They may be stylish, but you get bored of that after a month or 2, you get accustomed to it, second of all like wulf said, overpriced, paying more for the same components because their alienware?
Alienware has besides this a bad reputation regarding duration and the cost and time of getting your components fixed if something breaks down, even under warranty.
Oh and WD have i mentioned(if this hasn't changed) that alienware is owned by Dell?
MT