I've had my 60g cube up and running for several months now and currently have the following fish...
* Tank-Bred Kamohara Blenny
* Zebra Moray Eel
* Springer's Damsel
I love and would highly recommend all 3 (I'd try to find a smaller zebra moray though). I also plan on getting a leopard wrasse (Macropharyngodon meleagris), a pair of tank-bred neon gobies, a pair of white bonnet clowns, one of the Wetmorella wrasses, and hopefully a Red Sea mimic blenny if I can get my hands on a decently priced one. Here are some other suggestions...
* Assessors
* Fairy & Flasher Wrasses
* Longspine Cardinals (Zoramia leptacantha)
* Pearly Jawfish
* Orchid, Springer's, Sankey's, or Indigo Dottybacks
* Royal Grammas
* Possum/Pygmy Wrasses (Wetmorella)
* Fang Blennies (Meiacanthus)
* Chrysiptera Damsels (Springer's, Tracey's, Rolland's, Azure, Talbot's etc.)
* Chalk Basses
* White Spotted Pygmy Filefish
* Ecsenius Blennies (Bicolor, Midas, Tailspot, Linear etc.)
* Elacatinus (Cleaner) Gobies (Neon, Sharknose, Goldline etc.)
* Watchman/Prawn Gobies
... Good luck :fish1: