Depends on the nature of the trouble.
If I needed someone's ass kicked: Gibbs, no doubt whatsoever.
Wrongly accused of murder: Tony DiNozzo. Tony would know what I was going through (from multiple personal experiences), plus he's a great investigator and we would totally makeout afterwards. *nods*
Aliens try to abduct me: Walter Skinner. Umm...yeah. He can just show up for no reason at all. Aliens, bees, hangnail, whatever.
Aliens try to shag me: Captain Jack Harkness. I know he's not really a detective or law enforcement, but c'mon.
For all of the above I would want Stella Bonasera and Abby Sciutto processing the evidence. They're awesome at it and they look way hot while doing their jobs.