There's plenty of salt in the food that I consume when backpacking, between dehydrated meals, GORP, Clif Bars, and jerky I've never had symptoms of lacking sodium or felt the need to supplement with electrolyte drinks, if anything there's a surplus of sodium in my trail diet. Post hike, a nice sized Gatorade upon arriving back at the trailhead is always nice of course.
I've used Hammer HEED on trail runs lasting more than 10 miles or so, any mileage <10 plain water is sufficient, even for 100F afternoon runs. In the 20+ mile range I've found Hammer Perpetuem to be the best in feeding my body and replenishing lost electrolytes through excessive sweating- backpacking rarely, if ever, causes me to sweat to the point of inducing cramps due to low electrolyte levels.
Here's what I will occasionally throw in my bottles for a trail run, but never for backpacking, like I said, my typical trail grub takes care of salt for me:
Hammer HEED (excellent)
Hammer Perpetuem (sustained activities lasting several hours)
GU Brew (good, kind of sweet)
S-Caps (great for long sustained activity, if sodium is the objective these are easier than fiddling with powdery sugary drinks, but does nothing to stabilize glucose levels )