I played with it too.  I say no, you do not need it.  Maybe we can come up with a list of reasons TO upgrade to Vista... I can rattle off a few reason for why to NOT upgrade to vista ;)

http://videosean.gotgeeks.com/i/WinVista-VM/ - use the &lt;and&gt; keys to navigate previous and next images, x key closes big image.

Plenty of screenshots there from when I was playing with it.  It's a very annoying OS.  Always getting in yo face and tellin me I can't change a setting or move/delete a file.  Then again, it's probably perfect for the other 90% of windows users :P