In reply to kieran b:
> (In reply to Horse)
> [...]
>
> exactly the question i am pondering myself...any advice
A full sus 29er by Giant (Anthem 29ers get great reviews IIRC) if you want to go over things smoothly and easily and quickly.
A hardtail 26er if you want to feel more involved and like a bit more of a challenge, more than you do speed and smoothness/ride comfort.
What riding you do would affect which model of bike you choose, but that seems to be what you get from riding the above types of bike, going on what i've gathered by reading around a bit.