Now I love the clown gobies as much as the next guy (see below that my tank is goby-dominated) but I wouldn't exactly call a yellow clown goby "reef safe". It's more like softies/LPS safe.
I have one in my reef and it has pretty much destroyed a yellow mille I have. I still love the little fish, and even just put him in my 240g when I upgraded, but reef safe???
I like the midas blenny idea though. They swim around quite a bit and also have a ton of personality.