Over the years as my email volume increased I did a lot of fine tuning to my email process (stars, labels, read/unread management, etc). Once it surpassed a certain threshold (maybe 250 per day), I just cut out email management entirely. I don't archive, I rarely label, I just go through the latest, respond to anything pressing, and if there's anything that needs further followup it goes to my OmniFocus inbox where I prioritize all my work.

Email is critical to my work, but gardening it is not worth the opportunity cost.