Yeah - different Login Users is the best idea. Keep it in a Documents and Settings Folder. Even if you want to allow people safely into your My Documents Folder - you can put the folder in your Local Settings Folder in your user's Documents and Settings Folder - which will keep it safe from outside when they're looking and safe from them while they're on your acocunt with you watching.
But if you're not using XP or 2000 - then nothing beats layers and layers of complicated Folders. Or putting it in the System32 folder of windows with an obscure name - and closing down the Recently Used Files Menu on Start.
A Knight is sworn to Honour. His heart knows only Virtue. His blade defends the helpless. His might upholds the Weak. His word speaks only truth. His wrath undoes the Wicked.