At the bottom of Winterspring there are Frostmaul Giant in and below the area near the demons.
What makes these mobs so special?
They drop
Recipe: Greater Frost Protection Potion
http://www.thottbot.com/?i=24927
and with Naxx right around the corner, this baby can sell very well. 200g atleast on my server.
Also they are obviously lvl 60 elites, so they drop around ~25s per pop and have a fairly good chance to drop other goodies.
As a warlock they are complete cake, theyre suprisingly soft, for me anyway.