I have templar/chanter duo I like - though it is low on dps - probably glad + chanter would be best combo but I wanted a tank mostly

I'm also having assassin + cleric as second pair for similar reason (less dps from cleric but more from assassin and more healing power)

In general I think a tank or healer is a good class to get there first (even though slowest) as a healer can always really help lower alts you'd level later - keeping xp of lowbie high (out of party heals)