I was alternately amused and disappointed in Mark Dunn’s Zounds! A Browser’s Dictionary of Interjections. It has a lot of fun stuff (including cartoons by Sergio Aragonés, who is evidently still alive), but a lot of omissions and errors, as well. Mr. Dunn does acknowledge the magnificent contributions The Simpsons has made to our interjectional zeitgeist, but then does not mention C. Montgomery Burns in the entry for excellent. In my experience, almost any time that word is used interjectionally, it is done in the Mr. Burns voice, and means something like my evil plan is coming to fruition. Used in jest, of course. Yep.
Tolerabimus quod tolerare debemus,
-Vardibidian.

Instead of the Burnsian excellent, my friend Eli used to substitute e-egg salad. A fine substitution for Burnsianisms or the sandwich-filling of your choice, by the way.
The other night, I pulled that out at a writer’s group and cracked everyone up. It was a fine thing.
peace
Matt
And I often see “excellent” used online with fake HTML markup before and after, to wit:
[Mr. Burns] Excellent. [/Mr. Burns]
Or
[tents fingers] Excellent. [/tents fingers]
What I’m saying is, Mr. Burns totally owns that word.