Wellllll...
FPS Creator is great for drag and drop wysiwyg game creation. HOWEVER it is quite limited without any sort of modding done by a programmer, and of course it can only make FPSs. Ply's mod and Airmod etc are excellent mods but they're not official and sometimes difficult to use.
Darkbasic Pro is great to make any sort of game, but it requires learning programming, of course. This is actually a lot simpler than it sounds if you follow some tutorials, and you can make some really good stuff with it - take a search for EVOCHRON or RIFTSPACE, both made in darkbasic.
DO NOT TOUCH
the 3D game creator - it's fun, but not if you're serious about makeing games.
I'm sure other people will come in to tell you about Unity 3D etc - I've never used them, but apparently they're really worth it too.