What to add to my current 3?

Looking for input on what to add to my current group i am running now. It's a group of a Paladin, Magician, and Cleric. It is running really well, especially with my Magician's pet - which does a GOOD amount of damage by itself. So the thought of adding another Magician is definitely possible for me.

If i were to add more toons, i am thinking about another Magician, and Enchanter possibly, With either a backup healer / secondary healer, or invite another player for that 6th slot.

Any input / thoughts / ideas are appreciated.

Thanks.