Which is better???

[cichlid2006]

I would go with 1 and a few silver dollars. Avoid tinfoils because they get 12"+, need a decent sized shoal and move like rockets so they really need more than 6ft to shoot across should they get spooked and from what I hear that is quite often.
With that footprint you really have the options for extra cichlids, maybe 2 or three more 8-12" ones.

 

[BenSow]

Which would be better in a 100 gallon 6 foot long tank.

3 oscars

1 oscar and 2 BP's

1 oscar and 3 Silver dollars or Tinfoil barbs or other???

Also please tell me the awful things about having an oscar. You can also tell me the good things as well : ).

Id go with choice number 3... I always love movement in the tank and 3 oscars will just burn a hole in your pocket they'll eat like pigs