I have to agree with Mordor on the proportional representation, here in Scotland we have a list top up system for the Scottish Parliement. This results in a coalition government where Labour are tempered by the LibDems. A good example of the benefits is the lack of tuition fees in Scotland, and also the free care for the elderly.
Another good thing is that groups such as the Greens have representation in Parliement. No votes are wasted. Currently for the Westminster Parliement if you don't live in a marginal constituancy then your vote is wasted.