With 2 utlility characters, you have the freedom to try em all yourself. I'd just go 2 dps at first, maybe feral on druid and use it as main, and elemantal on shammy, as slave. But once you really get into it, you will figure out how you want to do it. Also, for grouping, if you can tank and heal, you can very easily find DPS to fill in slots for instance runs. Early on spec/gear doesn't make enough of a difference to mean anything, so just go bear on druid and heal when needed on the shammy.

The plethora of options is also plaguing me. My initial idea for a 5 box team is pretty useless while leveling, as my druid does crappy DPS compared to my priest/mage. I should probably try to use him in cat form until his spells are up to par. I wanted him to be a boomkin, for the aura and non-squishyness, but you can't level a boomkin lol.