Halfling warrior + rogue, doable?
 

Is it doable to have an untwinked halfling warrior + rogue duo or will it require lots of downtime? Does the rogue compensate for the warrior's lack of DPS? This sounds really like an interesting duo to me due to the extra exp :)

If not, what's the main difference between having a druid and a cleric to pair with the warrior? Which one would be best for duoing?

assling good for the racial exp bump and the pure melee exp bump but i hope you like bandages if your both non twinked

You will definitely want to add some healing power to that duo. Otherwise your downtime will be horrendous. I would personally prefer a cleric/warrior duo over a druid/warrior duo. Dunno about shaman/warrior...

anything with any amount of healing power would go great with a warrior

Well, it looks like the rogue is out of the equation then.

So... druid or cleric for the second char?

I'm leaning more towards the druid due to the ports, DS and extra DPS. They also seem to have better buffs, although far worse healing.

Let's see if I can get my friend to try the druid of if I will play it myself (being an alt-addict really is bad XD).

Shammy warrior would be really great. Shammy buffs, including haste and sow, and debuffs. Plenty of healing power to duo with warrior. Shammy can also dps better than cleric.

Druid gets same healing spells at same levels as the Shaman does, until Velious. Druid would be nice for mobility, but I would take shaman.

Ogre shaman/warrior duo >>> anything you've offered.

You could do rogue/warrior. You'll be fine at lower levels and you shouldn't have too much trouble finding a healer from teens on.

Playing what you want is better than what is ideal.

^ this. Unless one of you wants to play a ranger. Then I take it back, you should go for something you don't want to play.

Rogue warrior will be fine at lower levels. Equip the warrior with 2 polished granite tomahawks and you'll cruise through the lower levels. As others have said, once you get to level 19 or so it will be easy to find a druid/shaman/cleric to join you for healing power.

Errrrm... I already have a ranger, admittedly, a low level one (level 5) but, apart from the experience penalty, I can't see anything wrong with it :)