I had planned on taking Slicing, Scavenging, and Investigation. As I see it, it gives me raw materials for my armor, weapons, and mods; the ability to get the rare schematics for those three categories; as well as some credits along the way. Also, I expect the slicing and scavenging will be useful in the Operations/Flash Points as an added bonus.
Then again, this only works for individuals who do not want to craft, or have friends / guildmates that can craft the items they want. As a final resort, you can poll the crafters of your particular server and trade materials for services rendered and call it a day *shrug*.