Alienware's strong point is laptops, although you'll have a hard time getting one here (they only do surface deliveries in N/S America).
I agree with their towers being overpriced, but their laptops are definately worth it. A while back i was looking for a laptop, and, even after price conversions, the alienware was cheaper than a comparable dell.
But...theres always the problem of the power supply (120V against our 240, stuff tends to explode).
If it's a tower, I'd say build it yourself, that way you can get exactly what you want, and although it takes a while to shop around, your wallet will thank you when it's over