Hiking isn't as dangerous as everyone is making it sound. Don't let a few freak cases get you down or stop you from enjoying the woods.
With that said, I always go prepared for dangers, or even inconveniences. Mace should be enough to protect you, but I also like a close-up weapon as well, just in case they still insist on closing in. Like
this. However, a gun covers both conditions.
Bug spray is absolutely necessary. You know this if you've ever experienced a chigger infestation. They are point-like insects which burrow into your skin and cause extremely itchy sores that last for a week or more. Hundreds of those all over your body is HELL. You will hardly be able to sleep. They especially like the more sensitive, hidden areas of your body where you REALLY don't want itchy sores. Ticks and lime disease are also a concern.
I always carry a snake bite kit. They make nice syringe-like pumps which generate a lot of suction, so don't bother with the old-fashioned kind where you cut yourself to get out the venom. Most people hurt themselves a lot more this way.
Take plenty of water, and a some calorie-dense food. My favorite is a 1:1 mixture of M&Ms and peanuts.
Take a basic first aid kit, even if it's just bandaids and Neosporen. The woods are a dirty place to have an open wound.
A flashlight is always a good idea. There's nothing worse than being lost in the woods when it's getting dark. And sometimes you find caves to explore.
This sounds silly, but I consider extra socks a necessity. Whether accidently dunking your boot while crossing a stream, or simply a lot of sweat, I can't stand wet feet. It will cause blisters and make hiking miserable. Protect your feet at all costs. Buy the best hiking shoes/boots you can afford.
Depending on how long the hike is, I might even take a backpack with things like sandals to wade in a river, or extra clothes. You never know when you might want to take a swim, so extra clothes or a towel are helpful. Or if you just sweat a lot, and plan on going to dine around other humans afterwards, an extra shirt helps to cut down on the "you look like a homeless person" stares. But that can be left in the car, of course.
I go on really long hikes with lots of gear, and camp overnight, grill steaks, drink a 12 pack, etc. So a trip like this is obviously going to require more gear. But I consider the stuff listed above essential for a typical day hike in the woods (as opposed to say, an hour stroll through the park).