For me, email processing is largely about getting my email box empty, and I try to separate the sheer processing--getting the mixed batch of incoming email OUT of the email inbox and quickly herded into groups--from associated tasks.
I don't sort my email, so stuff that I've opened that isn't actionable (where "copy for reference" would be an action) gets dragged to one unsorted folder for the year. This reduces any stress about what to delete; I just drag EVERYTHING in there, and do any thinning months later, when I can delete vast swaths of obviously never-gonna-care emails.
Stuff I just want to read more thoroughly gets dragged to a "Read This" folder. (That includes emails with links to webcasts and recorded meetings, etc., not just "read".)
If I tended to put a whole bunch of informational items into Evernote (not that I use Evernote), I'd probably just drag them out of the email inbox and into a folder named something like "Move to Evernote". If that were a fairly rote process, I'd do it when I'm feeling tired and un-creative.
Is it a project? Ok, then start a new one. Do I have capacity for a new project? If not, where does it go? If really important, then I should add it to projects and perhaps push another project to Someday/Maybe and, if I do that, which one gets tabled? Nothing fast about this, in my mind.
If an email threatens to become a new project, I wouldn't do the project-creation work while processing email. I'd probably drag it into an email folder with other potential project seeds, and process them another time, perhaps in the weekly review. So a potential project seed should take me less than a minute, at the email processing (or "email herding") stage.
If an email points to the need for a new meeting, I'd probably create an action in my system: "Meet with Fred's group about Blah; see email 'Widget bug'" and I wouldn't create the meeting right then.
And so on. I will knock off everything but quick and simple responses this way, and do the quick and simple responses as the last step of processing my inbox--or if none are urgent, leave them there, re-marked as Unread, for the next round. If I had a lot of them, I'd create a folder for them, too.
I realize that I'm just moving, not eliminating, most of the work, but that's actually my goal--I want my email box nice and clear, so that I can see what's coming in, and I want the moved work corraled in defined buckets, out of the inbox.