1. I've tried almost all of them: not caring, eyeballing it, the CN wright system, CN weight with "equipment", crossing off X's in containers/locations, and slots of various types.
2. I use a slot system that gives PCs around 6 to 14 items - with "purses" of coin, insignificant items, and bundles for ammunition/a few other items. I also use automatically encumbering items (for treasure - like carrying a fancy chair) and fragile items that have a 3/6 chance of being broken in combat etc.
3. I'm pretty happy with this system and it's well tested. It works well for shorter sessions as it keeps the amount of equipment reasonable and means things like light, food, and equipment selection are still issues. I tend to design dungeons with it in mind when it comes to treasure as well.