Hehe. AA ppl tend to hijack topics...
You could certainly make this into a QT tank or a betta tank, but I'd look to do something more interesting that will please you for years to come.
If you're willing to make a few changes (lighting, substrate, possibly
CO2) you could make this into a beautiful, small planted tank (I've done this, so has Allivymar; mgkaelen is considering it). If you're not willing to make changes, you could nonetheless plant the tank with Java Fern and Anacharis and make it into a lush dwarf cichlid tank, or a threadfin rainbow tank. The threadfins would be a joy to watch. You'd have to be careful on the dwarf cichlids, as many ACs would uproot plants. However, Kribs and Rams would love such an environment and thrive in it.
Dunno if you're looking to make a big change like this, but I know from personal experience that it can be really rewarding to have a more distinctive, less standard tank. My 10G has dwarf puffers and otos in it and it is always fun to stand infront of.
That's my $1.00-$0.98...