Your inbox is supposed to be for new messages, so why are you treating it like a task list? That's what a to-do list is for. Go through your inbox, write down the tasks on a sheet of paper, and archive the emails. Now work from your to-do list and add newly-emailed tasks to the list immediately.
Link to this | This doesn't fucking apply to me
Ubiquitous capture is yet another idea discussed in Getting Things Done.