I had a 5 gallon bucket in the floor of my pit, I had to fill it in with concrete. I stepped into it too many times, you are not looking down, always up. Make sure it is painted gloss white so that you can clean it up and also to brighten it up. I used 2x8 - 2x12s to cover my pit. You couldn't drive over them, but it would keep you from falling through if you didn't aim good enough. Plus that kept the warmth and coolness in the pit when the temperatures were extreme. It did tend to get fairly humid down there, so I kept a set of cheaper tools down there so I wasn't pack muling stuff up and down the ladder.
I kept one of those 500w halogen lights on the floor to light up what I was working on, but it generated way too much heat in the summer. Putting one of the boards next to the working area was a great tool and light rest. I built an oil pan holder out of some angle iron that rested on the supports for the covers, and hung down about 8 inches. That was about perfect except for buying one of the floor style with the long funnels.
If ventilation is an issue, grab one of those models that you see the AT&T guys using. they are about a cubic foot squirrel cage fan with a 8" house that you drop into the pit. You will end up needing a little extra height occasionally, I had a 2' step ladder, but a 2' x 2' platform about a foot or so high would have worked great.