I have a 125 gallon and my fish list at this point is:
Two false percs (they do better in pairs, IMO)
Two Bangaii Cardinals (also good in pairs)
Yellowheaded Goby
Royal Gramma
And then soon I'll be adding:
Three Lyretail Anthias (one male, two females)
Blue Hippo Tang
Yellow Tang
I was thinking about adding 6 Blue Green Chromis (nice schooling fish), but I think I'm going with the Anthias intead. Who knows, I haven't purchased them yet, so I could change my mind again.
Since you already have a b&w clown you might not want to add a perc, you usually need to stick with the same kind or they will fight.