Another example for the influence of voting systems:

In Germany, the voting system was recently changed due to some very problematic edge cases. While the new voting system has its own problems (of a similar severity), a newspaper used the opportunity to compare the distribution of seats in parliament among the political parties according to the 2009 election (under the old voting system) with the distributions that would have resulted from the same voting behavior under many different voting systems.

The results of this comparison can be found here. (Use the buttons saying “Niederlande”, “Türkei”, … to switch between different voting systems. The picture on the left is the actual distribution of the seats.) This is a nice illustration of how strongly a voting system changes the result, even without the influence of strategic votes. (For example, the conservative party (in black) would receive between 34 and 73 per cent of the vote.)

(And for any German-speaking folks who are interested, here's a description of the different voting systems in that comparison.)