Working processes have developed to include a variety of different means, including in my case the use of various bits of technology which complement the pencil, paper and piano which still form the fundamental part of my writing tool kit. The computer is certainly indispensable when working collaboratively with other media. If I am working on a ballet or a film, say, the machine allows me to make an object that can communicate an outline of an idea more directly to a non-musician than any amount of chat. I also use the synthesisers and computer as sound sources in themselves, as can be heard in my recent Vivaldi Recomposed project, for instance. I see this as a natural continuation of the search for new tone colours which has accompanied the compositional process throughout the entire history of music. Currently the focus of this impulse is in the realm of the computer; in former times it drove the development of the orchestra or the piano.
Coming back to the original question about the working model for composers today - this is a question that we can only answer on an individual level, by navigating our own path - a path whose direction is necessarily impossible to predict.