Jim
Barry has a point but I wouldn't give up on the big XT just yet.
You don't say where abouts you are but most places will have a mix of trails varying from the mild to the extreme. If your willing to take it easy and maybee walk a bit first to see what it's like you can explore green lanes on pretty much any bike.
Of course a bigger, heavier, more road biased bike will be harder work on technical trails but you can either revell in the challenge (
) or just stick to easier routes (which might be wiser to be honest).
Either way though don't go away thinking that you've got to sell the XT before you can do a bit of gentle trail riding. I've ridden trails on road bikes (two up on a TR1 with luggage down the Ridgeway was probably a bit un wise though) and I know others who have done this too.
My advice would be get in touch with your local TRF Group for some advice on gentle trails and have a go. See how you like it. If you think wow this is fun but the bikes a real handful then think about changing it.
I'd definitely have a go first, just exercise some common sense. The XT is a big bike and if you get it stuck or drop it on yourself you could have problems. The trick I think will be to choose your routes carefully but you certainly don't need th elatest hot shot enduro weapon just go trail riding.
Cheers
Richard