I'm sure others can give comment about technical stuff, but I'm still weak in that arena. I wanted to say though that I really like your visual play here. The way the keep is lit (like a beacon) and the beacon is shot in a way to be taller almost larger symbolicly (like a keep). Very nice I'm assuming you meant to do that.
I agree with Suzanne but am going to make a comment about the overall tonal range - mostly to its lack of a strong contrasting sky and foreground. I find most of the tones to be lacking in snap. I did a layer adjustment with levels as the constant and used the "dissolve' mode at 50% to get this image:
I think the darker sky works well with the shadow of the tree in the lower part of the picture as both tend toward pushing the eye back to the castle.
Mike
I haven't been there for years. A nice old building, as I recall. I think the exposure on the tower and the post is a little high - you ar starting to lose detail. I put it in the CS5 RAW editor and the highlights were just about to blow. I reduced them a little, then dodged the clouds a little in CS5. Good shot, with a nice composition.
On my monitor, Rob's looks a bit still lacking depth but his does maintain a better detail record in the fore-post. That is, I am sure, his editing program and having the ability to work in RAW. I am going to recalibrate my monitor later this evening as I have noticed several comments as to my images being overly brash. Hard to tell as they do print out quite nicely.