Fortunately, the next two propositions are easy. Proposition 5 requires a 2/3 majority to pass new taxes. Oregon passed a bill that made it hard to raise taxes, and as a result public funding could not react to changes in the economy, causing many problems with education budgets. So I am an adamant NO on Proposition 5!
Unfortunately it is a fact of politics in the United States that, while people want things from their government, ultimately they don't want to pay for those things. As such, measures that make it harder to raise taxes tend to mess up the government's ability to function. I find it a bit disgusting that people think avoiding new taxes is worth this sort of protection when we cannot even ensure civil liberties for same sex couples in Michigan, but that is neither here nor there, just a side bit of commentary.
In short, NO on Proposition 5!