It depends on what you are trying to show. Is it statistics? Is it a mathematical relationship? I would guess your are talking statistics. A pie chart is circular and is good for showing the relative distribution of groups in a population, for example, the distribution amongst a school of students on sport preferences. The circle represents all the students (100%) while the "slices of pie" each represent the number of students favouring a particular sport.
A bar graph or chart often represents frequencies so it's easy to see from the height or length of each bar which have the lowest frequency of distribution and which have the highest.
A line graph or scatter graph can demonstrate correlation between two quantities to see if there could be a connection between the two. This is useful for linear correlation.
A map graph could be used to show the distribution of average rainfall or temperature over a large area, perhaps over the whole world.
So there isn't a "best" or easiest; it's more about what you're trying to show. The larger the dataset the longer it will take to draw the relevant graph, and you need to decide which type of graph is going to be most useful before you attempt to draw it! Then you can plan the work needed.
