There's another option: Win 98.

When Win XP arrived, many Win 98 users said what many XP users say today: M$'s new OS is not quite ready for prime time.

In the past seven years, many of those people still say XP is not quite ready for prime time and have stuck with 98. As a result, they have stable, clean, virus/malware free, problem free systems that require very little maintenance.