Installing and patching The Witcher from it’s v1.0 CD to 1.5 is, I believe, humanly impossible.
First you download the huge 1.4 patch, only to have it inform you that you need to install the language pack. Grab that 400+mb patch, and it informs you that you have to have 1.4 installed first. Super cool, and not even close to actually having 1.5 installed.
Not to mention Windows 7 thinks you are installing a virus when you install 1.0, thanks to it’s DRM. So you can’t even play 1.0 EVEN IF YOU WANTED TO! Nothing beats disabled drivers when you load up after a restart. Good luck actually getting those OFF your machine too.
Legitimately waiting for a Steam sale so I can buy the game, again, to play it before the sequel comes out.
Hardcore Casual 
Yes the Steam version is definitely the one to get. Least painful of the various install versions.
Game disappointed me personally, but it will probably go on sale during the huge Christmas one at the very least.