Gear "Essentials":
1. Good pair of supportive shoes. They don't have to be steel toe or waterproof or anything, as long they support your ankles. Newer combat boots are a great choice for their durability and comfort over long periods of time. Don't cheap out on these or you will regret it!
2. Besides boots, eye protection is the most important thing on my list. Get a good pair of goggles (or sunglasses for outdoor events) that are ANZI rated for real ballistic protection, so you never have to worry about them cracking or breaking on you. I use Oakley SI Ballistic sunglasses for most games, and they are durable, comfortable, and very fog resistant. Again, don't cheap out; the comfort and protection of the higher end stuff make them worth the higher price.
3. Vest or Chest Rig with pouches to hold mags, dead rags, radios, etc. I've seen people load it all up on a belt for CQC, but for outdoors, I would highly recommend spreading it over a vest. Make sure to get a dump pouch for expended mags.
4. Gloves with hard (or at least padded) knuckles. You will thank us later; that is all.
5. Lastly, get some protection for your teeth. Whatever you find comfortable to wear should be sufficient, but this does not mean cloth over your mouth! Whether it be a paintball mask, mesh lower face mask, or a football mouthguard, make sure you have something hard between a BB and your teeth. I just had over $1000 of work done to replace a tooth after it was shot out in a game; it's not worth it.
Outside of this list, you can get whatever you want. There is no "overdressed" in airsoft.
