OP hasn't mentioned how s/he likes to play - solo or teamage. It's not super critical to know but can influence choices.
For primarily teaming I'd suggest /thermal is a very solid support set - great buffs for your team, and some amazing debuffs for your opponents. Melt Armor is highly underrated IMO and you can get it recharged quite fast in a good build.
I'd also recommend /storm and /poison as good solid secondaries with /Trick Arrow almost up there too. /Storm gives you great debuffs, keeps enemies away and generally throws stuff around enough it won't be bothering you too much. /Poison is almost all ST and reasonably melee focused, but is still deadly with some punishing debuffs and ways to reduce even AVs to poodles. /TA is a good all-round set, giving you some reasonable debuffs, good soft-control and is inexpensive in terms of endurance etc
For primaries I'd say Dark is by far one of the best in terms of control vs damage giving you goodly amounts of both and has some very useful -to Hit debuffs, whereas Plant is all about damage and holds. It's also excellent but Dark just edges it IMO. Mind is also excellent at control but its damage is slow (A Mind/TA is one of the most painful characters I've ever played. Nothing could touch me but killing anything was a challenge) although a lot of enemies are weak to Psi. Stone is very good at locking stuff down but again, not so much damage.
Ultimately, play what feels good and suits your style the best. I would strongly advise against playing FotM builds or following the crowd. In my experience, going left-field has often produced some amazingly fun results. My personally favourite controller builds are my Dark/Poison and my Plant/TA. If I'm ever in a position where I want to get something done those will be my go-to toons, often my first picks over any other ATs or sets.
Have many funs and welcome home