* Animated movies - it's ok if it's "flawed", as it's not supposed to be 100% real.
* Scenes really impossible to shoot otherwise - like people falling from great hights, morphs, gigantic machines impossible to build.
* Minor corrections - visible microphone, crew in reflexions, sfx correction (matte lines, or see the Exorcist special edition for examples of this)...
CGI still can't replace good old fashioned SFX, and we know it. Not a single computer generated ship made by ILM could look as good as Douglas Trumbull models in 2001 - and if it wasn't for his work, I doubt we would have ILM or even Star Wars today.