best case scenario?
Gaddafi is left to rule, rebels are crushed without western help, Gaddafi signs peace treaty with all nations who instigated war on Libya, trade lines are opened fully with the west, UN or US forces establish a military base close to Tripoli and/or Benghazi, human rights charges are dropped against Gaddafi.
ideally that's what our best case scenario is...however with so many sides involved all wanting different outcomes the most likely event is increased involvement until we put men on the ground, take land at massive cost to human life on both sides, kill or dethrone gaddafi, set up a puppet ruler, rebels will attack him and any attempts to stabilise the country in the belief that we are attempting to invade, we stay to try to fight back and it lasts 10 years with no real results either way.