When I get e-mail notifications from 3DGameMan for "my post," I'd like to something that makes it very clear to me (and others). How about:

From: 3DGameMan.com
Subject: [username] commented in [thread title]

This helps me keep track of which ones to look at (with the same subject) and which ones to look at and delete other messages.

Plus, "your post" might be a little vague if someone were to make a comment in a video review that don't relate to my post.