It has potential, but only if you choose the right fish and do the right maintanence. Oh and if you plan attaching it to the wall then you want to make sure that it is a retained FRAME, not just on a bracket attached to the wall. Otherwise it could potentially be quite dangerous.
In this tank which is almost deffinately between 25 and 30 gallons the best fish combination would surely be a school of cardinal tetra, i'm thinking 50-70. To clean up the bottom, pygmy or any dwarf species of corys, OR possibly ottos, probably about 5-6 total.
Deffinately use an external filter to minimise internal clutter to spoil the "picture" feel of the tank andmake sure you do at least weekly maintanence to keep the tank looking great. Be sure to invest in a magnetic bladed algae cleaner for easy and quick glass cleaning.
Ben