I recently purchased a Sager NP8690. It is slightly out of the ordinary and although I know Harry was looking for something more lightweight, some may be interested.
This laptop has Core I7 XMExtreme processor with nVidia GeForce GTX 280M 1,024MB graphics card. 6,144MB DDR3 1333MHz Dual Channel Memory and a 500Gb 7200rpm hard drive.
It does fly and at 3.3kg I don't have any trouble carrying it!
The screen is beautiful - 15.6” FHD 16:9 LED Backlit Wide screen (1920x1080) Super Clear Glare Type Screen/HDMI with Blu-ray combo drive.
Info is just in case anyone has been/is looking for something not available off the shelf.