In a trigger, I'd definitely be more inclined towards inserting into a queue and then having a job send the e-mails. Schedule for once a minute, and you're not getting too far from "realtime".

I use this one a lot in things like my maintenance procs. They send me alerts about a variety of things going on in the databases that I like to know about. With those, I send directly from the procs. But those are running under DBA authority, and need to do so, so there's no permissions issue there.