SQL Express, the free version. No you will not need to buy additional hardware (?will it need more memory?)
One of the problems they are having is creating a good installation package.
It looks like version 4 will be SQL
Version 4.5 may include health maintenance
Jon was already saying version 5 for practice management, I don't know if this was a slip.
Jon is trying to keep this backwards compatible. He is very aware that people want improvements without major changes.
