UPDATE:
After sitting on a few bikes and.. err pushing around one them in the shops it seems like the GT Avalanche 3.0 Disk Hydro 2010 is the one I will end up getting - the seat was reasonably soft, unlike on the XC2, Kraken and the Specialized Hardrock Sport.
There are the hydraulic brakes on the Avalanche 3.0 DH '10. The handlebars seemed a bit wide, but I will either get used to them or I could ask for them to be cut down as the guy I was talking to mentioned.