Sounds like you should start using flags instead ("stars" in web-gmail?) Then your todo list should be easily accessible through a filtered list of flagged messages. Most IMAP clients offer this out of the box.
I have labels for organization but once something is marked as read or out of my priority inbox (where starred emails go) is has an extremely low priority and might as well not exist. If it's in my inbox and unread it gives me anxiety not to action it. A Snooze feature is a perfect middle ground.
Gmail also offers a nifty "Starred First" view which keeps the last 10 or so starred emails at the top