Yes, Exz is right; it's impossible to say which genre is better. However, everyone mainly plays the genre they enjoy, meaning everyone chooses what's best for themselves. I personally love strategy games, action games, and RPGs. In general, until recently, I played almost everything, but now I don't have the time or money to buy every new release, so I only get very popular games.

I haven't played The Witcher yet, but I will definitely buy it, possibly even the expensive collector's edition, because I have no doubt that I will like the game, and it's always nice to have a beautiful DVD box with my favorite game, as well as a bunch of bonus discs, etc. :)