What kind of "editing" will you be doing ? I'd not recommend Photoshop unless you need some really specific tools for professional production work in advertising or something similar. I only use PS very sparingly, but on occasion there are filters I like which only PS is able to give me. I also use other filters from other software as a plug in to Lightroom, but you should understand what you need first.
Lightroom, Aperture, Capture NX are all extremely capable editing programs, and I'd even go so far as to say that I could actually live without Photoshop and only ever use Lightroom. Of course, this means being conscious of photo composition, because your options are limited in terms of cloning things out of a photo such as power lines or garbage cans etc... But then, that's really getting into another area which is more along the lines of being a purist or a total digital cowboy etc...
So, where do you stand with respect to how much editing you need to do ?
Doug