[MOD EDIT: Continued from the poll thread.]
Looking down at this one from the north, your political scene is certainly in a state of flux, but for the first time in the history of the state there's a good chance your about to develop normal politics down there (I am fully aware of the irony of a Northerner talking about normal politics). To put my cards on the table I have always voted SF, but that mainly due to a lack of other options. If/when FF come north I'll vote for them in all probability.
But if I had a vote in the next general election, I think I would vote for Labour or SF depending on what constituency I was in. What is certain is that FF simply cannot win this, no matter who is in charge or what sort on coalition they try to put together. But they will come out the other side with a new leader, and regain their credibility in opposition. They always do, and that is exactly what is happening to the Labour Party in the UK. Just like Gordon Brown, Brian Cowan is best hanging on for now, so the next leader remains isn't associated with busting the country in a few years time.
As for the next government, looking back through the history of the state, any time FG have formed a government in the past their main qualification for the job seems to have been the unpopularity of a FF government. After the UK general election its hard to know how seriously to take opinion polls showing the traditional 3rd party on the verge of government, but by the same token there seems to be an appetite for real change, and FG probably offer more of the same from brought to you by the other team from the civil war.
The big prize would be a result that will mean an incumbent Labour government up against a revitalised FF in 4/5 years time, and the start of proper left-right politics.
Where SF fit into that long term I'm not sure. They have half a dozen people who will be hard to budge, and will appear fresh faced and dynamic with the likes of Mary-Lou McDonad and Pearse Doherty, and maybe Theresa Ferris and Pádraig Mac Lochlainn. It all really hangs on Mary Lou McDonald getting a seat in the Dail and being able to take over the leadership from Gerry Adams. Once that happens there is an argument for moving towards merging with Labour to concentrate the left on one party.