Hate to say it, but this is definitely covered on this board. Also, I will tell you staright out, there is no "Best" for everyone. Some people like Bondo, others like ABS, some Plexi, Some JB Weld. There are allot of options, all with different advantages and disadvantages.
...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.