I'd say spines/regen, great AoE and pretty good ST damage output, and good survivability, especially wiht a support char backing you up.
okay , what about the support power sets ?
I'd either go Spines/regen or Spines/Drk - both good aoe capability.
Support I'd say a controller with /kin for the faster recharge time on attacks with SB( for the scrapper) and SP for yourself. However, I'd stongly suggest the spines/regen take Quills and Quills and Death Shroud for the spines/drk to obtain and maintain aggro.
Possibly Fire/kin for support and dmg later on - in the early twenties in the game I suspect the both of you would be avery powerful combination.
In short, you have +end, +recharge AOE damage, containmant dmg - heals, debuffs, aggro control, more dmg and pets.
Sounds good to me 
what would be a very good duo thorough out the whole game , im gonna be a scrapper and my bf is gonna make a def or troller . so what would be the best duo/synergise/powersets together ?