Prestone all vehicle concentrate from WalMart is a darn good choice and likely the best price too. Make sure to flush out the system before adding a diluted 50-50 mixture.
As always, the more antifreeze in the mixture, the lower the freeze point and the (slightly) higher the boiling point. Note: Boiling point is mostly controlled by the pressure cap rating.
But remember, water transfers heat best, so in things like race cars and hard working vehicles with marginal cooling systems, it may be slightly beneficial to move away from a 50-50 mix. A 60% water, 40% coolant mix is not much risk, as it will still protect the water pump and provide good freeze protection.
Here in South Florida, it is not unusual for me to use 70% water and 30% Prestone in my modified turbocharged engines.