It's important to have a goal in mind.
From your post it seems that you are not a newbie, so you more than likely have a good idea what you like and what you want. It may be a huge multi amp, horizontally bi-amped monster of a system or it may be a simple flea powered SET system; I think in all cases you it would be beneficial to have the complete system in your minds eye as you start. Nothing stops you from tweaking along the way.
From your post it seems that you are not a newbie, so you more than likely have a good idea what you like and what you want. It may be a huge multi amp, horizontally bi-amped monster of a system or it may be a simple flea powered SET system; I think in all cases you it would be beneficial to have the complete system in your minds eye as you start. Nothing stops you from tweaking along the way.