I would not recommend a drop ceiling unless you have a lot of height. The drop ceiling will take about 4-6 inches of height, so that you can put the tiles in at an angle and work the tiles around until they fall into the rails. Also, the installation cost for a drop ceiling and dry wall are fairly equal. A drop ceiling will reduce the value of the basement. Drop ceilings are frequently used in home theaters so you can deaden the sound but the acoustic tiles are more expensive. Installing dry wall on a ceiling is bear and it is fairly cheap to have a dry wall contractor install it for you. I would leave some access panels near spots you have to access (e.g., water valves).
For flooring, I would have carpet if that is what you like. Personally, I would use vinyl wood-look planks and use an area rug above it.
If you are going to finish a basement, put some thoughts into the functional elements and not just the finishes. You need to look into heat/cooling the space (I suggest a mini-split system but you may need several for different rooms), hiring a plumber for the bathroom, and installing a lot of can lights in the living space