I've seen a number of folks posting the common question "how do I deal with my email?" It must be a popular New Year's resolution. Here's my solution, which I got somewhere about 4 years ago. I like to cite my sources, but there's no way I'll find it again. 4 years is a geologic era in internet time.
1) Pull out in some way (tag, create a new folder, etc.) email that you've gotten since January 1 that actually needs to be dealt with. Not adverts about discounts for an online store that you might shop in by the next month, you'll have 4 more adverts by then. These are requests, bills, anything that requires action.
2) Create another folder or tag titled "2013 Unfiled." Put every other email in there. All 758 of them.
Now you have a very clean inbox AND a searchable archive if you find that you truly did need something.
A potential Step 3 is to create more/better folders/tags to dump emails in. If you had 758 emails in your inbox, then the folder system is probably not up to snuff. For example, I need to use my "Little League" folder more often, because baseball emails tend to pile up. I need to keep them to keep track of practice time changes, etc.but then they later become irrelevant.
Next year, do the same thing. You'll have a "2014 Unfiled." And each year there will be a bright shiny new inbox. Then it's up to you when or if to delete the previous "Unfiled."
2010, I'm looking at you.