I use Photoshop cs3 as my main photograph editing tool, using pixelmator for simple tasks i.e. cropping, then I use photomatix pro for tone mapping, but if your just starting out and want a simple to use, good to look at application then either Lightroom, aperture or PS elements are all good tools, you just need to decide what your aiming to do, as previously mentioned by OreoCookie Both lightroom & aperture are workflow management tools and pretty good at it too, but have a look at pixelmator for basic editing 😉