Yes, Voice.com is the most expensive (publicly announced) domain ever sold – Domain Name Wire
Some domain sales lists include domains that shouldn’t be on them.

When MicroStrategy announced this week that it sold Voice.com for $30 million, I noted[1]: “This is a record–by a large margin–for a public domain-only sale.”
Some people took issue with this. What about CarInsurance.com? VacationRentals.com? Each of these has been reported as a domain sale for more than $30 million.
Yes, each of these has been reported. And misreported. Sometimes by domain investors who want numbers to seem bigger and often by press making domain stories. Even GoDaddy’s own site lists these domains[2] above its Voice.com sale.
The problem with these other sales is that they were full web businesses, not just domain names.
Another domain often on the list is PrivateJet.com at just over $30 million. Right now that domain forwards to FlyVictor.com. So you’re telling me someone paid $30 million for that domain to forward it?
PrivateJet.com was a cash and stock deal. Equity in private companies is easy to manipulate.
Let’s say Andrew Rosener of Media Options decides he wants to buy Domain Name Wire to add to his domain media properties. Instead of paying cash, he buys it with equity from a company he just set up. He and I agree the equity is worth $50 million and he gives me half of the company. Wallah, he just bought Domain Name Wire for $25 million! But we all know that’s not really the case.
If a public company buys a domain with stock and there’s no lock up and it’s liquid at that price (e.g., not a penny stock or OTC), then it’s as good as cash. But equity in a private company is not.
The best list of true domain sales[3] is at DNJournal. There is one on the list that I have an issue with (Fund.com) due to some weird stuff with the company, but I understand why Ron Jackson included it after much questioning.