I would second this request. I would like to create a master dashboard with a filter. I would like to be able to put a link to the dashboard that pre-populates teh filter when the dashboard opens. In my case it is a Job Status dashboard. When the user clicks on the link associated with the Job I would like the dashboard to open with the filter for the job filled in and active.
At this point the filters don't have a default setting that you can apply. The best you can do is pre-filter the reports to that user which would mean they can't access the full data set, so you could create one dash that has just theirs, and then give them a button to the full data set but the filter won't co-mingle those for you at this point.
That was the work around I ended up using, but it would still be better if you set defaults for the filters.