OOH I like the one in the middle one with the rocks. You can almost feel your hands bruise as you scrape them against the rocks. I grabbed these and played with them some. iPhoto is OK but really Photoshop is the standard tool. There is an Apple version but it might be expensive.
I squeezed a wee bit more contrast with channel mixer. The white highlights are blown out though.
I left the sepia tone in this one but used highlight/shadows to recover the exposure of the trunks. There is some kind of distortion running down the left side though.
This one was difficult compositionally because of that pole in the middle and the underexposed building. It was tough to bring out the "OUT" sign and yet keep drama in the sky
I still want to check out using the filters though. Polarizers may still have a use as may graduated filter; they would help to prevent blowing out the sky while underexposing the rest of the image.
Dave, Hoya and Nikon filters are very good and you can't really tell the difference. What you can gain from them, at least on film, outweighs any added distortion.
Cheers,