Well, MPs did in the end vote to hold a referendum on introducing a new voting system - the Alternative Vote - to Westminster elections, but it is hardly a game changer. It will only happen if Labour win the next election outright (a coalition with the Liberals would presumably produce a more proportional suggestion), and then it is only a commitment to hold a referendum. But it has at least focused attention back onto the thorny issue of what voting system is best for parliamentary elections. The Liberals must be kicking their historical ancestors for ever having rejected the Tory suggestion of a PR system back in the first decade of the twentieth century, but the Liberals then thought they did quite nicely under FPTP thank-you very much, and had no idea they were on the brink of being relegated to eternal third party status.
The BBC have done an interesting projection on likely outcomes of AV using previous election results. The principal losers seem to be the Tories, who would benefit far more from a properly proportional system or even a hybrid of the type that runs in Scotland. Labour benefit to a small degree - explaining Gordon Brown's preference for this particular alternative - while the Liberals do not exactly break through their electoral barrier. If the only alternative is AV, we may as well stick with First Past the Post!