there is (depending on whose word you take) only one remote hole in the default install in the last six years. No other OS has under gone the line by line code audit that Open has, Theo D. and the others on the project do great work and have amazing results. If you want it free and you want it safe, OpenBSD is the answer. If you want to pay and you wan tit safe, STOP from WangFed is the answer, but I don't think those are sold to just anyone.
visit to get a better idea....