This was a pretty good step for me, but I thought I could go one better this time.
I found a whole bunch of these white plastic drawers in our basement. We used to store baby clothes in them. A good wash and they were as good as new and really a ton spiffier than the ripped up cardboard boxes I had my envelopes stored in previously.
The labels I made tie in my two colors: apple green and bright blue.
These drawers will live under my big desk, keeping all my envelopes within easy reach...