always take commendations!
and use them all for blue mods before leaving the planet.
If you are to chose between comms and blue or purple mods - take mods.

never take even orange or green or blue armor - because social gear ter 2 (Nar Shadaa & Belsavis) are easy to get.
well, except you want the certain look - like i've hunter Mercenary Prototype Elite Armor set on Taris :-)
but you can do it after you'll ding 50.

and one more hint - don't use Corellia commendations on blue mods.
soon you'll get much better purple mods through Illum and Belsavis H2 dailies.
Instead of mods buy from Corellia Coms Vendor orange offhands (shields, generators, shotguns, vibroblades) for you and your companions!