@NikoDoby:
I use Aperture, so keywording has been relatively easy. I enter a new keyword once and after that I drag it on to the photo I want keyworded. And if you think keywording a few family members would be overkill, you do not want to see my list of people keywords. I shoot at school for the yearbook, so I have lots of photos of classmates. Of course everyone I know has to be keyworded. That's my rule.
Because of this, I have nearly 100 people registered in my person-keyword database.
And it's been useful. Sometimes someone want photos of themselves, and it's been quick to find them. That's why I want to add more keywords to make looking for landscapes, macros, or whatever faster.
I have considered doing ratings with stars, but I'm not good with that. Usually I ask someone else which photo they think is better.
I wish I had the Faces technology of iPhoto in Aperture, as it would speed things up. But hopefully in Aperture 3 they'll take the auto keywording to a whole new level. Since many compact cameras are able to automatically decide which scene mode to use, shouldn't software be able to as well? It would be great if it could automatically keyword landscapes, macros, portraits, etc.
Anyway, I think I'll also use some of the keywords that already came with Aperture, as they include the keywords you suggested as well.