Wise people learn from thier mistakes
wiser people also learn from the mistakes of others
there's some great suggestions for what you could do with a 20 gallon long
at http://www.cichlid-forum.com/article...cutter_20g.php
there's other suggestions at
http://www.cichlidrecipe.com/cichlidrecipe/crp22.htm
no doubt there's tons of other suggestions elsewhere.
Something to help you decide what fish to get would be to get your tapwater
tested. how easy is life when the fish you own suit the water that comes
right outta the faucet without having to mess around with it too much.