This is tough, with a capital "T".
Out of the PFs named in this thread so far, I like Kevin Love. Kevin seems to me like he can be a leader out there, as well as put up solid numbers.
He just turned 22 a few days days ago, and last season's stats? 14 pts, 11 rebs, 0.4 blks, 2.3 assists, and roughly a steal per.
Anthony Randolph appears to be the closest ability-wise to KG - but will he be a leader out there?
I like Al Horford as well, but I don't think he's leaving ATL.