The Peanut Butter Wonka Oompas that we knew as kids are long gone.
Wonka (now owned by Nestle) revived the name a couple of years ago when the new movie came out to create an assortment of little chewy fruity flavored nuggets.
I think the old Oompas also came in other flavors, like strawberry, but I'm not having much luck getting confirmation on that. The feature of the Oompas was that the top was peanut butter and the bottom of the disk was chocolate. (M&Ms are layered with a center of peanut butter then a chocolate coating then a candy shell.) The package was along and narrow wrapper instead of a shorter rectangle. Here's a photo of the old wrapper:
M&Ms makes a couple of seasonal Peanut Butter M&Ms that some people think are kind of close to the old Oompas. One is the Easter Speck-Tackular Eggs and the other is the limited edition Shrek Peanut Butter M&Ms.