I am consdering using a double post sorting on my blog, with both tags and categories.
I hope that will work in the long term.
However, the recent developments of wordpress are beginning to be, if you forgive the word, scary.
It has been sometimes advised to give up on categories and use tags instead. Much progress has been made with tags integration.
This is an open question, : do you think that in the long term, as far as the future can be forecasted, wordpress will keep on supporting BOTH tags and categories ?
Thanks a lot if you have an idea about that :)