Depending upon what you will be using that class for there are benefits to both. A death knight would commonly provide a high potential for gold income for it's ability to solo higher content, thus meaning the death knight succeeds in being able to efficiently "run/escort" your twink. Death knights also have the ability to play as a tank, aka more variety and has the option for queing as a tank ---Shorter que times/ control run speed/ likely to gain multiple sets of gear at the same time. The Wealth of Nations, Adam Smith, brethren.SUPPLY&DEMAND.--- A hunter is able to kite certain mobs and most definitely run a low level through a dungeons with relative ease. If you're going to prioritize doing lower end content such as Blackwing Lair, Serpent Shrine Cavern, etc. I would say a hunter most definitely if you find the aesthetic approach to the game to your liking, especially with transmogrification coming along ( Tier Sets ).
Opinion Summary:
Hunter - You don't care about PVE 85
Deathknight- PVE 85, Gold/Justice-Valor Points