When I look at advice on which Photoshop package to buy I find it covers functions and doesn't tell me what they are for, kind of tough if you're not familiar with the functions. So what package (eg Elements, Lightroom, Full CS5) are needed for:
Buying any of the above is like buying a chest full of tools at a hardware store. Over a lifetime perhaps a dozen will see constant use, but the rest are there if needed. The price of the program reflects the size of the chest to some degree. Upon opening the program, it may seen quite overwhelming, but it is learned one tool at a time. I don't think there are many people in the world who know
ALL of Photoshop, and it is not necessary to do so.
I use Photoshop CS5, and skip a generation in most cases. CS5 was a huge jump over CS4, which I had skipped. It brought several brilliant new tools, which I use constantly.
1) General photography with a DSLR using RAW
All will do the job. Needless to say, Elements is a sub-set of the CS5 tool-set. Lightroom is particularly strong in a studio, commercial or news environment, where a great number of images needs to be managed and processed. The vast power of layers in Photoshop, dictates that it is the application I choose as my digital darkroom. I also use Corel Paint Shop Pro for anything of a more graphics nature. Each has quite opposite strengths. Handling type and vector graphics, creating textures for 3D and the like is more efficient in PSP. Processing photographs is more efficient with the power of Photoshop.
2) Creating a brochure (with images)
This is possible with Photoshop, but a desktop publishing program would be better suited to the task. Photoshop's type handling tools are minimal. Process the images in Photoshop, and combine them with text and graphics in a DTP application. I have no idea if Lightroom has the capability, so would not comment one way or the other. I did a lot of this during the 1990s, but now work primarily in multimedia and web, so have not kept up with software for this task.