Any place a libertarian supposes just government intervention it is to allow coercion-free individuals life, liberty, and property.
Roads: In general, I prefer privatized roads, like the 407 near where I live. If roads are to be built they should be financed by individuals, corporations, counties, townships, and regions. Ideally these would be funded by donations. Social pressure could be used (ie, a Google map of every house that didn't pay its share of the cost) to expose to the community who the cheapskates are, but tolls at city entrances are fine too. I could talk all day about an ideal libertarian state with contracts being enforced everywhere, but for practical purposes this is a non-issue once brought down to the township and one of the last things that would be worth privatizing. Take the example of an enemy of yours buying up all the land around you and stopping your freedom of movement, do you not have right of way to leave? The way these things should be paid for if they are to be done by the government is through the rent of land from the government. No one created land. No one can morally claim first ownership of it.
Radio: Radio should be treated like property. Rented from the state, just as land should be. People have the right only to jam the radio signals within their own airspace, no further. The state has the right to enforce destruction of property.
National Defense: No standing armies. Lots of nukes paid for through the rent of land. Make it a impossible for another nation to attack you. When all you have is nukes the whole world knows how you will respond to an attack. Voluntary organized (by the government) army and navy reserves for responding to national disasters and enforcing national waters.
Rat Poison => Tylenol: Fraud. Murder. The problem with the FDA is the "F" and the whole idea that they can stop a fully informed adult from taking a drug because it doesn't have their stamp on it. This could also be done through organizations like Consumer Reports. Quibble: Do people sell street hot dogs with rat poison in them? No. People are generally good and we don't need to assume Rat Poison is behind every Tylenol bottle. We would save more lives by subsidizing vegetables (which granted, I'm also against).
Public Schools/Voucher: Ideally donations and paid for by the parents. The whole system needs to be reworked. Why can't I teach math to highschool kids? Oh right. The government says that, regardless of whether or not I'm teaching at a public school, I need to have a teaching certificate. That's a problem. Schools are prisons that only server the bottom 90th to 70th percentile until at least grade 10. But again, this, if done through tax, should be local _only_. No child left behind is a terrible program and a perfect example of letting cities and states be the deciders of education.
When I say pro-government interventionists I (generally) mean the government interfering with mutual exchanges between consenting adults absent force or fraud.
Surely if the roads are funded by townships or regions it's no different to the current system (i.e. it would need to be funded from some kind of regional tax, rather than a federal or statewide tax as it is now). I think roads are often used because they're a good example of something which seems to be a natural monopoly, where many people find a libertarian treatment lacking.
I'm skeptical about the viability of a donation system for anything, but as it's never been done in practice, it's hard to have much meaningful discussion about it. It's worth noting that even Friedman thinks the government should fund education (and believes in some form of accreditation at least for teachers) (http://www.schoolchoices.org/roo/fried1.htm)
Roads: In general, I prefer privatized roads, like the 407 near where I live. If roads are to be built they should be financed by individuals, corporations, counties, townships, and regions. Ideally these would be funded by donations. Social pressure could be used (ie, a Google map of every house that didn't pay its share of the cost) to expose to the community who the cheapskates are, but tolls at city entrances are fine too. I could talk all day about an ideal libertarian state with contracts being enforced everywhere, but for practical purposes this is a non-issue once brought down to the township and one of the last things that would be worth privatizing. Take the example of an enemy of yours buying up all the land around you and stopping your freedom of movement, do you not have right of way to leave? The way these things should be paid for if they are to be done by the government is through the rent of land from the government. No one created land. No one can morally claim first ownership of it.
Radio: Radio should be treated like property. Rented from the state, just as land should be. People have the right only to jam the radio signals within their own airspace, no further. The state has the right to enforce destruction of property.
National Defense: No standing armies. Lots of nukes paid for through the rent of land. Make it a impossible for another nation to attack you. When all you have is nukes the whole world knows how you will respond to an attack. Voluntary organized (by the government) army and navy reserves for responding to national disasters and enforcing national waters.
Rat Poison => Tylenol: Fraud. Murder. The problem with the FDA is the "F" and the whole idea that they can stop a fully informed adult from taking a drug because it doesn't have their stamp on it. This could also be done through organizations like Consumer Reports. Quibble: Do people sell street hot dogs with rat poison in them? No. People are generally good and we don't need to assume Rat Poison is behind every Tylenol bottle. We would save more lives by subsidizing vegetables (which granted, I'm also against).
Public Schools/Voucher: Ideally donations and paid for by the parents. The whole system needs to be reworked. Why can't I teach math to highschool kids? Oh right. The government says that, regardless of whether or not I'm teaching at a public school, I need to have a teaching certificate. That's a problem. Schools are prisons that only server the bottom 90th to 70th percentile until at least grade 10. But again, this, if done through tax, should be local _only_. No child left behind is a terrible program and a perfect example of letting cities and states be the deciders of education.
When I say pro-government interventionists I (generally) mean the government interfering with mutual exchanges between consenting adults absent force or fraud.