My change for the presidential election (and for any elections for a single entity body). First, abolish the Electoral College, these days it just leads to situations where we have unintuitive results such as the 2000 election, where Al Gore had a larger popular vote yet George W. Bush still won. The president represents the nation as a whole and should be elected as such.
The other problem with the presidential election comes from its voting. A normal popular vote system is very simple to implement and explain but it leads to unintuitive situations. Many people can't vote for who they'd really like to vote for because they'd feel their vote would be wasted. This has historically been a problem for Independents and the Green Party. Coming into our next election, it may be a problem for conservatives given the split between standard Republicans and the Tea Party may cause a fragmentation of their voter base that will work in the Democrats favor.
I advocate the use of the single transferable vote system. Using this vote for our system, each voter ranks as many candidates they want to support in the order they want to support them. So their first choice would be #1, second would be #2, third would be #3 and so on. They can rank as many candidates as they want.
When the votes are tallied, each vote initially goes to their first choice candidate. Then, it is decided if it's impossible for any candidates to win. For example, if the total number of people who picked a candidate (at any ranking) is less than the current number of votes for the current highest candidate, then that person could not possibly win. Any impossible winners are then removed from the running and their votes are redistributed to whatever the second choice on the ballot is. If there are no impossible winners, the candidate with the lowest number of votes is dropped and the ballots redistributed. Redistribution continues until one candidate has more than half of the remaining votes.
This system would give independents and third parties greater support since people can vote for them without 'wasting' their vote. Our current, simple voting system only works perfectly when there are two candidates. There is no perfect voting system for multiple candidates but there are certainly better ones than ours. Ours, because it works perfectly in a two-candidate system, has forced our politics into a two-party system, making it very hard for anyone who doesn't fit into one of those categories (or isn't willing to change their beliefs to fit into them) to be elected.
