To Upgrade or not to Upgrade

Ok, here it is. Windows ME has begun collapsing into its own black hole, dragging most of my applications and internet connections into its Stygian depths. I bought the PC from Dell with WinME installed, but I can't find the backup installation disks (if they were even delivered) so I can't reinstall.

Real basic question: Should I upgrade to WinXP (Home Edition)? My PC should handle it - it's only about 3 years old. Or should I find Win2000 somewhere and only go that far? Or should I ditch the whole thing and attach a cup and a string to an abacus?

Let's just say Windows crashes at the most innoportune times lately...