2fargon...having/installing several Graphic programs won't tax your system, only running them all at once 'might' ...
I have several graphic proggies...probably more than 8 ....and even with a dozen instances of PSP6 running at the same time I see no impact at all.
Re Photoshop versions....get the 'latest'/'newest' you can afford....and look forward to an extensive learning curve. PS is still the 'Industry Standard' used by amateurs and Pros alike.
The most important point, however is that programs do NOT make 'awesome walls'.....'awesome artists' make awesome walls.
Programs are simply the tools used....and have exactly no intrinsic talent of their own....