Raven:
From a software perspective, you should buy a dual processor. With the exception of Quark, the other programs you seem to depend on are dual processor optimized. For example, PhotoShop will share its workload between both processors. InDesign, also optimized for dual processors, will probably replace Quark, and you can get a competitive upgrade from Adobe. To you, that mean faster renders and more productivity. You seem to be a graphic artist, like myself, so my hardware advise to you is get a low end G5 if money is tight, but at least make sure it's a dual processor. As for OS 9 bootability, think of the future and go OS X. You always can use classic for those few programs that lag behind the times.