Bugmail is a running joke at Mozilla. Nearly everyone I know that works with Bugzilla (especially engineers) complains about the amount of bugmail they get. I too suffered from this problem for years, but with some tweaks to preferences and workflow, this problem can be solved. Here's how I do it:

E-mail preferences

Disable e-mail completely for cc changes and other things that don't generally matter to you. For me, this includes the keyword field and even the dependency tree.
If you follow components, make sure you only get mail for NEW bugs in that component. You can cc yourself explicit to things that you decide to care about. This one has been huge for me. I follow 5 components, and I would get hundreds of additional mail per day if I got mail about every change to them.
Set "Automatically add me to the CC list of bugs I am requested to review" and "Automatically add me to the CC list of bugs I change" to "never". See the workflow section below for more on this.
Set-up an e-mail filter to automatically mark your own changes as "read". I like to get mail for this for better searchability, but there's no reason it should be something I need to look at when it comes in. You can do this by matching against the "X-Bugzilla-Who" header.
If you filed a bug you no longer care about, Mozilla's Bugzilla now has an "Ignore Bug Mail" field that will make it stop mailing you about it.

Here's what my full e-mail settings look like:

And here's my Zimbra filter for changes made by me (I think the "from" header part is probably unnecessary, though):

Workflow

This section is mostly just an advertisement for the "My Dashboard" feature on Mozilla's Bugzilla. By default, it shows you your assigned bugs, requested flags, and flags requested of you. Look at it at regular intervals (I try to restrict myself to once in the morning, and once before my EOD), particularly the "flags requested of you" section. The other important thing is to generally stop caring about a bug unless it's either assigned to you, or there's a flag requested of you specifically. This ties in to some of the e-mail pref changes above. Changing my default state from "I must keep track of all bugs I might care about" to "I will keep track of my bugs & my requests, and opt-in to keeping tracking of anything else" is a shift in mindset, but a game changer when it comes to the amount of e-mail (and cognitive load) that Bugzilla generates.

With these changes it takes me less than 15 minutes to go through my bugmail every morning (even on Mondays). I can even ignore it at times, because "My Dashboard" will make sure I don't miss anything critical. Big thanks to the Bugzilla devs who made some of these new things possible, particularly glob and dkl. Glob also mentioned that even more filtering possibilities are being made possible by bug 990980. The preview he sent me looks infinitely customizable: