A few pro-voting arguments I'd like to make:
1) If you think the difference between the approach of the two parties is minimal and that they're both corporate whores and that it doesn't matter, you're partly right, but overall I would say you're not paying close enough attention to policy creation and implementation. There is a big ideological difference between the two parties and that difference literally can affect millions of lives. The notion that there is no difference or that the differences don't matter or that it's all team sports in the end is dangerously naive. It's an accurate assessment in some areas of policy, but it's really not in others. Those small differences do matter.
2) If you think a third party vote is a wasted vote, that's also naive as the presence of those votes for another party brings us closer to having a multi-party system. Every time a third party gets a significant share of the vote, it forces the top 2 parties to capitulate to the influence of those parties in order to assimilate them or work overtime to crush them so they don't upend future electoral success. Also, in order to get on and maintain ballot access in many states (CA and NY being two of them), a third party has to receive at least 10% of the vote in a gubernatorial race. Building and maintaining alternative parties requires voting on those lines, which, in my view, is critical if we want to someday have a more mature, less bi-partisan democracy.
3) Even if one is uninterested in the big contests like the Presidential race, local elections really do matter in ways people seldom grasp until they have a run-in with local government. So many things about the way you experience your city and your neighborhood are the result of who's in those seats. So even if you're disenchanted by the BS of the big election, it's worth taking the time to educate yourself about the positions of the local and regional candidates and vote for them. Most ballots allow piecemeal voting.
What's unfortunate is that to really know enough to have a truly informed vote, you have to do a lot of reading to see how candidates ideologically align with you. You have to read pieces of legislation and read studies on policy initiatives and look at your local, state and federal budget. A lot of it is deliberately obfuscated because it suits those in power to keep it that way. But we are fortunate to live in a time where so much information is made transparent and researching candidates is easier than ever before.
Use
Common Cause to find out who your local representatives are.
Use
Project Vote Smart - The Voter's Self Defense System to see what the candidates' voting record looks like.
Use
Fact-checking U.S. politics | PolitiFact to analyze policies and their impact on Americans.
Use
OpenSecrets.org: Money in Politics -- See Who's Giving & Who's Getting and find out where the money is coming from that influences candidates and legislation.
Use
snopes.com and assess whether the things you've heard and come to accept as historical fact even happened.
But if all this is too much work, it's probably not worth voting. One is free to complain, but their complaints can't be taken very seriously.