Cybertech, scavenging, underworld trading.
I'd reccomend that for everybody's first character, useful and profitable. You ready got 1 character but it's good to get access to all the mods and armorings.
Since you don't want to craft gear, then this ^ ... If it wasn't for your stated aversion to crafting gear (something I'm personally a huge fan of since prototype quality schematics are easy to learn and much better than most mission rewards and usually slightly better than even modded gear filled with commendation mods), then I'd suggest Armormech. Especially for trooper since you, and 4/5 of your companions will all use Heavy +Aim gear.
But I digress, just wanted to throw my two cents in supporting the cybertech route. The only other suggestion I would have would be armstech, since every mod except barrels/hilts are easy to obtain with commendations. Most of the commendation hilts/barrels though are epic fail. But, as far as I know (don't quote me on this) armstech has little to no real use/demand come end game when compared to cybertech.