In response to my blog post about voting tactics yesterday, Russell claims that there are no tactical voting problems in instant runoff voting, immediately following that in the next paragraph with an explanation of how there actually is tactical voting in Australia's Instant Runoff.
Err. In my opinion, every instance of tactical voting is a problem. Your mileage may vary, of course.
Next, "proportional representation" does not equal "everyone is a candidate everywhere". For the house of representatives, Belgium is divided into a number of "kieskringen" each of which elects a predefined number of candidates into parliament (the number of candidates per kieskring depends on the number of people living in that kieskring). This way, we have proportional representation while still having the members of the lower house representing geographic regions.
Note that I'm not claiming proportional representation is the best election system ever; it still doesn't allow me to fully explain what my vote preference is. However, proportional representation does not have the brokenness of Instant Runoff voting in that with IR it may happen that placing one candidate before another on your ballot may actually hurt the cause of the former in favour of the latter.