I'm looking for software in order to put files from bracketing together under Lion and create HDR image.
The software I like best currently for HDR merging on the Mac is Nik HDR EFX Pro. It has a number of different ways you can vary the merge and so far has some of the more realistic tone adjustment I have seen.
They have an Aperture/Lightroom and Photoshop plugin.
I am not MAC user, but under Windows I used opensource Luminance HDR and as I see, it is also available for MAC, so you can try it.
I use Lightroom on a Mac to do most of my usual processing, so I opted for the LR/Enfuse plugin.
It is a "donationware" product, so the price is up to you, and the tool itself works wonderfully, and integrates extremely well into the Lightroom workflow.
You could look at HDRtist and HDRtist Pro. They are both easy to use programs that on the easier to use side, with adjustment sliders for controlling the HDR effect(s).