Anyone know what bug this is? It looks to be eating a bumblebee. The other day I saw one hauling off one of my honey bees

That's one of the Robberflies. Some of them are also known as bee killers.

I looked around and I think this is the one in your picture.
http://bugguide.net/node/view/...

Thanks.... That's the one.. I also saw one about a week ago carrying around a housefly.

You sure were right to call your bug a hunter. They are quite efficient at catching their pray, usually in flight or midair. I've seen them catch horseflies twice their size, and other robberflies. I've also seen them catch grasshoppers and wasps. Anything flying is on the menu for robberflies. For the most part I like having them around, except when they catch bees.