Speculation as to possible suitors pretty much starts and ends with Seagate since Western Digital is in the early days of their merger with Hitachi. Western Digital by comparison paid about $4.3 billion for Hitachi, however Hitachi had a much larger share of the market to back up the price. Samsung still has a very robust component business including memory chips and flat screens, however it never seems to have established itself in the hard drive sector.
Neither Samsung or Seagate have made any official comment on the matter, but expect to hear more in the coming weeks.