I used to have just a weekly recurring untimed appointment on my Clie every Friday for "weekly review" with an attached note of DA's checklist and I too found that I spent a great deal of time getting in to empty.
Now I have a second weekly recurring untimed appointment for every Thursday afternoon called "Get in to empty".
That way, when I get to my weekly review either late Friday a.m. or early Friday p.m. I'm only dealing with, at most, a couple of hours worth of inbox accumulation.