You're going to be better off with a betta for starters, balas need 6 foot tanks because they get over a foot long, are very active swimmers, and really should be kept in schools.
A few other "tankbusters":
Pacu- 3 feet, over 30 pounds!(and despite what Petco says, there are NO small species)
Common plecostomus- 2 feet+
Redtail catfish- up to 5 feet
Oscars- 12 to 15 inches
Kissing gouramis- 12 inches
Jaguar cichlids- 18 inches
Jack Dempseys- 12 inches(I hear that the Electric Blue JD's top out at 8 to 10 inches)
In other words, research before you buy fish, most of what you see at the pet store isn't adult(AND severely overcrowded, don't think stocking like they do doesn't require a lot of work just to keep them alive long enough to sell), some of them are barely out of the "fry" stage. 5 gallons is good for a betta or some shrimp, 10 gallons is pretty limited, 29 allows for bigger tetras and some of the dwarf cichlids, 55 gallons is where your choices really start to open up.
I learned a lot the hard way, but that was way before even computer bulletin boards, let alone the internet. It's a lot easier to find out stuff now.
