Thanks for the responses. Aparently I wasn't clear enough: it isn't on the GUI boot screen, it's on the "choice" screen (as Ben describes, except mine is still there). Doesn't hurt anything, just curious.
BTW, I went to the "confirmation" site and my copy is legal.
Never messed with "Media Center" in any way.
Thanks Ben, glad to know I'm not crazy (contrary to what others might say!)