Pally/Priest Duo

So started my duo team and was wondering. Is disc the best spec to go for lvling? Or should i go with Holy for now till i get higher?

what are you trying for? pure questing?, tanking and healing in instances?, pvping?
priest alone shadow is the best leveling spec

Well mostly just been dungeon lvling...Pretty quick and the accnts r RAF'd so easy enough few lvls per dungeon and gear. Mostly tank and heals every time

I would probably go with a Ret Paladin (DPS spec) or Prot (if you're doing dungeons) and a Disc Priest.

Disc because your healing is decent, if you take into account your mitigation abilities it is very comparable to Holy.

As a Disc Priest, you get Penance which is your best DPS ability.
Eventually, Smite will heal for as much as the damage it deals (talented).
PW: Shield will prevent a good amount of damage too.

All my priests (six of them) are Disc.
But Holy does work too, if you solely want to heal and won't PvP or DPS much.

Dont see me pvping much. Mostly dungeons and pve only.

Basically go Holy, if you only want to heal.
And want your play to be... Target has been damaged, give them a heal to get back to full.
You get an extra AoE heal, for a slight advantage at this.

Go Disc if you want to both heal and DPS.
Your heals won't be nearly as good as Holy, but you'll prevent a lot of damage and not need to heal as much.
You've got quicker "twitch" healing too.

Both Holy and Disc are very effective healers; it's a preference call which way you go.
I suggest Disc, because you can assist with the DPS, which can be important with only two toons questing... and it won't impact your ability to heal dungeons.