No it's not. Take your bias elsewhere. Vista is a better OS then XP and support for XP will end before Vista support. I'll agree that Vista is a resource hog but just turn off all the eye candy and you have yourself a faster, more stable, longer supported OS than XP.
Vista is so stable that the company I work for (Watlow Electric which is multi-national) has officially abandoned Vista to go back to XP.
There are currently 2 laptops in the entire company that are using Vista. Mine and one of my managers. Mine is being switched to XP tomorrow.
I know how to use computers. I have all the eye candy and stupid alerts turned off. The programs that run the worst (for me) on Vista are Microsoft Office, Microsoft SQL Server Management Studio, Microsoft Internet Explorer, Firefox and Microsoft Visual Studio 2005.
4 of those are flagship applications for Microsoft and they run like complete junk on the flagship operating system.
In 2-3 years time, after 2 or 3 Service Packs have come out, I am sure that Vista will be an awesome OS. Just like XP was crap until Microsoft fixed it over the next few years and now it is at least stable.