Windows 2000 benefits :

Windows 2000 has lower system requirements, and has a 
simpler interface (no "Styles" to mess with). 
Windows 2000 is slightly less expensive, and has no product 
activation. 
Windows 2000 has been out for a while, and most of the 
common problems and security holes have been uncovered and 
fixed. 
Third-party software and hardware products that aren't yet 
XP-compatible may be compatible with Windows 2000; check 
the manufacturers of your devices and applications for XP 
support before you upgrade. 


Windows XP benefits :

Windows XP is somewhat faster than Windows 2000, assuming 
you have a fast processor and tons of memory (although it 
will run fine with a 300Mhz Pentium II and 128MB of RAM). 
The new Windows XP interface is more cheerful and colorful 
than earlier versions, although the less-cartoony "Classic" 
interface can still be used if desired. 
Windows XP has more bells and whistles, such as the Windows 
Movie Maker, built-in CD writer support, the Internet 
Connection Firewall, and Remote Desktop Connection. 
Windows XP has better support for games and comes with more 
games than Windows 2000. 
Windows XP is the latest OS - if you don't upgrade now, 
you'll probably end up migrating to XP eventually anyway, 
and we mere mortals can only take so many OS upgrades. 
Manufacturers of existing hardware and software products 
are more likely to add Windows XP compatibility now than 
Windows 2000 compatibility.