All three have the potential to be great fights IMO. According to Arum TRs first choice is GGG, according to Hearn the first choice for Froch is Jr, I think K2 and Golovkin would be happy with either, though I suspect they'd prefer Jr as the easier and probably (in the US at least) more lucrative option. Any of these options would make me happy, though my favourite would be Golovkin vs Froch, hard to say on venue though - UK might be the best for Froch vs GGG, but Froch s Jr would be huge in Vegas.