I'm not yet really familiar with the game and all the spells and stuff, so this is a bit hard to assess for me. I want to have a really strong party and I was wondering which cleric order is strongest according to you guys.

A lot depends on your personal philosophy and game playing style. My comments are only from a powergaming perspective.

There are two good blasting clerics: Morninglords of Lathandar and Stormlords of Talos. If you want your cleric to be able to be able to dish out some damage as well as healing and buffing try one of these two.

If you want a melee cleric, then Tempus is a good choice as Axes are the best weapon in the game (best magic weapons are axes) and Tempus gives you two axe feats for free. The strength bonus is also nice.

For sheer power, however, I would recommend a Dreadmaster of Bane. Their domain spells are not great, their domain powers are nice, but not spectacular. What makes Dreadmasters so good is that there is a Banite quest in the game that will give a Dreadmaster a +2 WIS. That means extra spells, a +1 to your spell DC's (combined with your domain bonus, that's +2 to Will save spells), and an extra +1AC if you have at least one level of monk as a mix-in. If you do the standard once-through-in-normal-once-more-through-in-HOF that will mean a +4 WIS. If you start with a WIS bonus race and begin with a 20 WIS, put all you level-ups into WIS, drink both potions of Holy Transference and wear the Every God's Ring you will have a cleric with a WIS of 40! That is a lot of spells and a spell DC that is unbelievable.

Thanks a lot!

I think I'll go with Lathander then since I like to be good (as in: not evil), but I also hate being weak, so now I'm pretty sure Lathander is a good choice.

I understand not wanting to be evil. While Talos and Bane are evil (I think. I really do not know that much about the Realms, I have always been a Greyhawk fan myself), their clerics can be Chaotic Neutral and Lawful Neutral.

There's also a special quest for Painbearers of Ilmater later in the game if you're interested in that.

By the way, does anyone actually use any of the cleric order special abilities (e.g. Pain Touch)? I have never found them to be that useful.