That is not to say that voting third-party is a "waste," but that by doing so you're giving what may be the "more evil" option of the "lesser evils" that much more of a shot at winning the White House.
I'd choose to look at it this way: Which of the more-likely candidates is going to effect your life in a more positive (or less negative) way? Its not the best way to think about it, but in the long-run, unless we drastically alter the way in which we govern ourselves, we're stuck with a two-party system.
The two statements I bolded are in disagreement with each other. People voting third-party are trying to alter how we govern ourselves, and by you basically saying it won't do any good is adding to the problem, not helping.
If everyone quit believing in the hype or voted for actual solid plans, not just "change" then McCain and Obama wouldn't be on the gorram radar.
Anyone who calls a third-party vote a waste or say that you allow the other guy to win, is the exact same as the anyone but Bush camp. The lesser of two evils is still evil. There is no other way around it. Find the candidate that represents you, not the one that isn't the guy you don't like. If you don't like the main candidates and don't know enough about the third-parties then if you want to actually call yourself a responsible voter you will do the research yourself.
WARNING: Researching third-party candidates will require reading more in-depth than just catch phrases like "Change we can believe in." You will likely find yourself reading actual policy proposals. See, third-party candidates aren't wasting their time coming up with cute catch phrases, no they are actually focused on policy.
I honestly believe that if everyone in the US took the time to research third-party candidates the two-party system would end in a single election. But instead we will happily allow ABC, NBC, CBS, CNN, and Fox to spoon feed us.
I proudly put a Barr car bumper magnet on my Rabbit this week. After repeated comments of, "What's the Libertarian Party?" and "Who is Barr?" I have to say that I am more fed up with the voters in this country than I am the politicians. I get pulled into debates that usually end with their final statement being, "Well it is change from Bush," or "Can you trust a man with Hussein as his middle name?" I just want to slap them.
For the love of God, people, vote for your principles, not to keep the other guy out. We are selling ourselves out to two parties that basically have the same crappy policies with just a few differences here and there that don't mean jack.
As out of place as this is, it reminds me of V for Vendetta when he tells all the people that the condition their country is in is not the fault of any politician or any media personality, but the fault of them, the people. All of them. The blame lies on us, not the parties or the government. WE allowed the government to become what it is.
[/soapbox]
I'll go check my Fantasy Football teams now.