For me personally, a fairer system would be one with a proportional outcome. Under the present system, it's possible (and actually quite common) for a party to win a significant majority of seats with less than 50% of the vote. AV isn't a proportional system, but would be likely to generate results somewhat closer to a proportional outcome.
My personal concern with this referendum is that AV is no-one's "ideal" solution. Most people who have been campaigning for voting reform really want to see a proportional system. But if people who want proportional representation don't go out on Thursday and vote in favour of AV, then supporters of FPTP are likely to interpret the result as a mandate for not changing anything, and in that case I don't think we'd see a similar referendum on proportional representation in my lifetime.
We're a few days away from the Referendum on what voting system to have. Well, not a full choice, as the only options are FPTP and AV. Oddly, the STV system doesn't get a look-in, despite it being used to elect members to the Scottish and Welsh Assemblies, for example.
Anyway, Rachel has written a good post on this, and I agree with her conclusions:
Let's not keep FPTP, people.