IMO, it's the most effective combination - but you must install the 1.1 patch, otherwise, your spear will not get added damage with increasing skill.
The spear is a long reach weapon, rather fast(!), and doing a huge damage. The dagger is quick (so that it won't extend your recovery time), it brings additional "attack" value, and it can be magical. According to my experience, spear + dagger is better than 2H spear. Of course, spear + sword is even better than spear + dagger but you must be able to become master both in spears and in swords.
Note: 2H spear gets one "dice" more, it does not do 50% more damage.Two swords are far less effective than spear + dagger/sword. Swords do not have additional damage. Mace + sword need not be bad for paladins, I have no experience with paladins.
