In describing the supported upgrades, the article said:
Any edition from SQL Server 2000, can be upgraded to SQL2K5. These include Enterprise, Developer, Standard, Personal, and Evaluation editions. In order of precedence, low to high, Desktop can be upgraded to Express, Standard, Developer and Enterprise Editions (XSDE); Personal to S,D,E; Standard to D and E, and Developer to Enterprise edition.
This isn't the case though. While running a testing scenario I attempted to upgrade SQL2000 Personal to SQL2005 Developer. The attempt failed out with a message that it wasn't a supported upgrade. On checking the upgrade information article at MSDN, it confirmed that SQL2000 Personal can be upgraded only to SQL2005 Express, Workgroup, or Standard -- not Developer or Enterprise. The other editions of SQL2000 also have much narrower upgrade paths than the article indicates.
Ref -- http://msdn.microsoft.com/en-us/library/ms143393(SQL.90).aspx