We have three candidates for Governor of Virginia this year, and pressure is on by a vocal minority to vote for libertarian Robert Sarvis to send a message, improve the diversity of opinions, or disrupt the two-party system. Voting for Sarvis is unlikely to achieve any of those ends, so I think that's a poor reason to vote for him. You should only vote for Sarvis (or any other candidate) because his and his party's platform most closely matches your values.
Of course, with only three choices -- or six, or twenty -- finding a close match is unusual. So how can you vote your concience? We have to think in broad strokes. So, broadly speaking:
If you are socially and economically moderate to liberal, vote for Democratic Candidate Terry McAuliffe and the Democratic ticket.
Although McAuliffe's opposition has tried to paint him as an extreme liberal, most Democrats remember him as part of the pro-business, centrist "New Democrat" group. You can read his position on issues here. He is the closest thing in this race to a status quo candidate, although I think under his administration we would see core government services refunded, a liberalization of the state's marriage laws, and possibly a slight liberalization of the state's drug laws.
McAuliffe is a pragmatic choice for liberals in the state, as his election will, at the very least, stymie Rebublican and Tea-Party attempts to roll back reproductive rights in the state and reshape electoral processes to the Republican's benefit.
If you are socially conservative and anti-tax, vote for Republican Ken Cuccinelli and the Republican ticket.
Ken Cuccinelli is the sitting attorney general. You can read his position on the issues here. Cuccinelli is in the radically smaller government camp, but his tenure as Attorney General has been defined by his attempts to get the Supreme Court to reconsider its ruling on anti-sodomy laws, resistance to Obamacare, his anti-choice stance, and is on recent record saying laws banning sex outside of marriage should be enforced more often and that birth control should be more difficult to obtain. If you are a conservative Christian Republican or Tea Party, then Cuccinelli and the Republican ticket are for you.
Cuccinelli has tried to characterize campaign ads highlighting his socially conservative agenda as "scaremongering," but the Washington Post editorials recently called him out on campaigning centrist and running right, saying he's bragged about it before.
If you are a libertarian, you should vote for Robert Sarvis; you're on your own for the rest of the ticket.
Robert Sarvis is running a strong campaign for the libertarian ticket in Virginia this year, I suspect largely because mainstream conservatives are dissatisfied with Cuccinelli's social agenda. Sarvis's platform sounds traditionally libertarian: his policies support weak government largely unable to regulate both personal and corporate behavior. As such, he takes some positions that are typically considered contradictory, such as a significant liberalizing of drug and marriage laws, deregulation of gun purchases, dismantling the public school system, and rewriting the tax code. If this sounds like you, vote for Sarvis.
Side note: Many libertarians claim Sarvis's low numbers are due to voters feeling like they must choose between a Republican or Democrat or waste their vote; I think there just aren't that many people comfortable with the libertarian platform.
If you are disgusted with all three options, think politics is a corrupt and unredeemable system, or think all three of these guys are equally bad, do not vote.
Seriously, stay home. Although there's a lot of pressure to get out and vote, if you don't like the system, don't think your participation matters, or don't understand the issues well enough to be able to see the distinct differences between the candidates, we are all probably better off without your input.
If you are a Republican or a Democrat but are very upset with your party's choice…
Then you need to get involved in the process a lot earlier than the general election. Your local organizations are easily approachable, and you have many opportunities during the year to drive the selection of local and state-level candidates. Waiting until the general election is waiting too long.