Interesting thread. As a Summoner near level 50 I would say that I would like to have a Bard and a Red Mage in every party. Both of them for MP regeneration and various buffs/debuffs.
With these two jobs in my party, I can afford the luxury of being a healer AND letting my avatars contribute to the damage pool, skillchains and magic bursts with no downtime. Sadly SMN, BRD and RDM are very rare to come by and I rarely ever see all three in the same party.
P.S. I need to level my bard job to level 30+ so if anyone below level 30 needs a Bard, feel free to ask me my current level and if the setting is right, I will switch jobs and join your party.
See you on Lakshmi!