I've found, depending on what you like fighting:
Lots of easy enemies: Elec/Nin.
Few Hard enemies: DM/Nin.
Dm/Nin is has so much utility, so much damage, it's really the perfect stalker.
@Mechaniker
Official Old Angry German Guy of CoV.
My Characters: http://boards.cityofheroes.com/showthread.php?t=247787
I would have to say spines.
Burst damage ST : Energy Melee (yeah it's still good for Stalkers, not so good anymore for Brutes and lolTankers)
ST dps: Dark Melee
Aoe: Elec Melee, I find it better than Spines because Thunderstrike crits all the time (the ST portion) and the AoE part crits half the time from hidden. And L. Rod does not unhide you allowing for a TS / AS crit. Plus elec only lost a skippable power when ported to Stalkers (L. Clap), all the other sets lost powers you'd likely pick for Aoe.
And in Bill Z Buubba's thread for scrappers and brutes, elec is till ahead of Spines for st damage.
Despite what people say, I am still partial to Energy Melee paired with Ninjitsu. My Stalker is an absoulte monster with that pairing. Once you get capped melee and ranged defense you are pretty much good to go against anything.
"People love to talk, but hate to listen." Alice Duer Miller, American Author (1874-1942)
I'm trying to decide what would be a good primary set for a /nin stalker that mostly solos and groups every once in a while. Right now I'm leaning toward Martial Arts because my last stalker was a MA/SR and I enjoyed the set. However since /nin has some control components I'm wondering what would be the best primary to take advantage of /nin's strengths. Your thoughts?