Well from the ones you listed I've only seen, Povetkin, Arreola, Scott, Greeburg, JD.
Funny the youngest is 26 and the oldest is Hereluis whois 30 and I don't consider him young espcially taking into consideration he has only 13 fights.

Uuuummm! I think from that lot I would side with Greenburg slightly BUT he lacks power IMO, I also like Arreola but he lacks some skills and needs to work on that dept. I also think those 2 have fought the better opposition out of the lot.

I would also like to add Eddie Chambers & Dimitrenko to the list.