There's nothing like a bad fall to ruin a good evening run. The right headlamp is essential.
A common problem for runners is going through batteries in a flash. You can buy rechargeables, but that can be a hassle. Black Diamond, however, makes a rechargeable headlamp specifically designed for trail running. It’s called the Sprinter, and it sells for $80.
I’ve been using the Sprinter for about a year, and I really like it. Plugging in the charger is easy and I get five good hours on high and 60-plus on low. It's super bright (68 lumens), and the beam pattern is designed for optimal “throw” for runners. If you’re on the road, you can turn on a blinking red strobe in back.
Another rechargeable option is Petzl's Tikka 2 Core ($85). It doesn’t have a taillight like the Sprinter, nor is it quite as bright (35 lumens) but it can be charged via a USB connection, and even powered by regular AAAs in a pinch.
In a non-rechargeable headlamp, I like the AAA-powered Mammut X-Shot ($90). It's ferociously bright (200 lumens!), and lasts as long as 15 hours on high. Like the Sprinter, it has a red blinker on the battery pack.