The best, most accurate gas gauge I've ever had is the one I'm still using now. It's a chopstick.
I took a round chopstick, cut it in half, made careful measurements of the depth of my tank, and used a triangular file to mark the chopstick accordingly. Then I sanded and polished it up so I wouldn't have wood bits in my tank.
When I take the gas cap off and look inside, I can see the gas that's in there. But even with broad daylight, or a flashlight, it's hard to tell how much. That's why the chopstick is so great. You just pop the top, stick the tank, and read it.
The only advantage to an analog (needle-type) gauge is that you can read it instantly and while in motion. But they are often affected by that same motion, and even when stationary they are not as accurate as we'd like them to be. My gas mileage is so good, I only need to check it once in a while. I've gotten used to just taking out the stick every now and then. It's really not a hassle at all.
