YMMV, but my painter recommends:
1) Semi gloss on kitchen & bath walls and doors, trim, baseboards, etc throughout the house
2) Eggshell on utility room walls (pantry & laundry). I think eggshell would also be nice in powder rooms.
3) Flat everywhere else.

We went with flat on the walls throughout the house for the first time ever. We like it! We used semi-gloss for the trim. We still have eggshell in the bathrooms as they were painted several years ago. Looking at the eggshell compared to the flat, I do notice imperfections more with the eggshell, which was the point of moving to flat. We don't, however, have painted walls in the kitchen anywhere where they are likely to be splashed and in need of washing. If we still had a painted backsplash, I think I'd use semi-gloss.