Vergil is a great name. I love how it sounds and looks. Then again, I am a gigantic Latin nerd. And yes, this is the only true CORRECT way to spell Vergil. His name was Vergilius, you can't really argue with that. I would seriously consider this as a name for a boy.
A different spelling doesn't change my sense of this name. Unfortunately, it seems like this name has been dragged into the "redneck" stereotype by popular entertainment. It just reminds me of the characters on "Mama's Family" or a one-liner from Jeff Foxworthy.
In the popular video game known as 'Devil May Cry' the main character had a twin named Vergil. I suppose the translators for the game decided the spelling with an E instead of an I would be more suttle. In the game, Vergil was a very strong-willed character. I thought he was cool. =D
Vergil is a really nice name. I prefer it over Virgil because it has a better feel to it. Though sometimes when I imagine someone named Vergil I think of a pervert. =[ But not every Vergil is like that. I would name my son this name.