Hydrostatic is the most accurate, but you probably won't want to spend the jack for one. You can pick up a pair of cheap calipers. In my opinion, that is the second most accurate option. You can use the impedence machines or whatever, but they are effected by too many variables and they have always read way too high whenever I have done it.
For me, I weigh 177 and last night I was calipered at 4.3% BF. I mulitiply 177 x .043 and it comes back with 7.6. That's how many pounds of fat I am carrying. 177 - 7.6 is my LBM which includes, muscle, bone, organs, anything that is not fat.