It's worth thinking about what other things will be in the space after it's decorated. If you have lots of colourful ornaments or painting/prints then you might want to have something understated and neutral/plain so that the focus is on the items being displayed.
A hallway can look a bit bare in a pale colour scheme which would look great in a living room. And medium dark walls and light woodwork can be a bit stark...Stark contrasts show off architectural features mind. So you have to decide what features you want to highlight.
My preference in hallways is for a less pale wall, but as books, photos etc soak up light - if you have a wonderful photo montage you might want to stay on the lighter side. Wall art looks great if there is a strong contrast between the pictures and walls. Very pale is conventional - although a deep colour also works, it's a question of personal taste.
It's also worth thinking about how often you want to redecorate. There are fashions in interior decor as with all things. Some colour schemes date very quickly - do you remember the red/white kitchens of the 80's?
I love the colour contrasting chairs and sofas look. It makes a room very cosy and welcoming. I'd be careful about being too matchy matchy with the cushions though. A bold print on a bold plain fabric might be a bit hot. You could think about contrasting textures, velvet against leather, silky against damask. Think about shapes and sizes as well. If you have lots of cushions all the same size and fabric it might look a bit corporate.
