Paul
really nice work on your desktop wallpaper. My preference is for the last version, with Lake Barrine straight. I feel the angle detracts from the picture and does not do the image justice.
A couple more suggestions (which are only
my preference and you do not need to try them out) are:
Make the bird photo smaller, perhaps the same size as the waterfall image, and have the Lake Barrine image run underneath the bird and along the bottom, with equal spacing between the borders of the 3 images (to add symmetry). I feel the images would be stronger as seperate units on the screen as opposed to layered, as you currently have them displayed.
Reduce the size of the signature & instead of having a lone camera with HUGE lens, perhaps include a photo of yourself taking a photo (or setup ready to take a photo - you may need help with this

). I think this would personalise the image more, and people could identify you with the pictures, instead of just a camera with a rocket-laucher attached to the front of it.
These are just a couple of thoughts that popped into my head whilst viewing your images. I'm not saying they're better, just something to think about. If you agree & want to try it out, or it sparks further ideas....so be it
PS..great photos by the way !