There are still plenty of unanswered questions about Vince...
My Vince Foster theory is that he whacked himself in one of safe houses that the White House uses when they want to meet people on the sly.
Then, after they found the body, some moron decided they didn't want to burn the location of the safe house, so they moved the body to Ft. Marcy park.
Personally, I believe Vince Foster was killed by Jimmy Hoffa on orders from the Illuminati. But this was not before the Men in Black came out from Area 51 to abduct Ed Sullivan and Elvis.