There's basically two thought's I'm having about the flash forwards we've seen so far....

a) The flashforwards might not be real and just show the 'worst case scenario' for the person involved - Think about it, in the FF for Jack (last ep of S03) we saw him totally down to the ground, depressed and looking like he's on the virge of a breakdown. In the 401 FF, we saw him actually in good shape - picking up his life as a surgeon again and generally not doing bad. I know he says to Hurley that he is thinking about growing a beard, but that might just be a joke / something to throw us off. The beard he has in his own FF certainly doesnt look like it's been well cared for.
In the 401 FF it centers about Hurley - and he doesnt seem to be doing that well. Going crazy, seeing Charlie, having a not-so-fun life in the mental institution again. Agreed, he's not on the virge of total doom, but he's not doing well either... I'm looking forward to seeing the 402 FF - wondering if it's someone doing real bad then....

b) Who is to say the flash forwards are from after the whole series (so after s06) ? I would like to think we actually will see the 'oceanic 6' go back to the island to care for the ones left behind (if they're still alive) - to me, it sounds very feasable that we'll see people go back to the 'real world' in season 4 or 5, but having to go back for some reason. I don't think these flashbacks are the final thing, but part of what we'll see in one of the coming seasons.

What are you guys' thoughts on this?