I have read somewhere that you can adjust Windows Vista in function of your computer system.
On my old computer a PIII 600 Mhz I was able to run WinXP faster then W2K,...strange indeed.
OK,...the comp. had 640 MB ram,...but still,....
But I guess Windows Vista would be a little bit too heavy to run it properly! It is graphical more intense (more like MacOS X effects) and will require more harddisk to install.
I used this computer for approx. 6 years,...(long time I know)
Now I own a PIV 3.2 Ghz with 2 GB ram,..so I assume Windows Vista will run smooth,...(at least I hope,..you never know what 2006 will bring)
Microsoft will also claim that Windows Vista will be more secure then WinXP SP2,...yeah ok,...what is security really,... I do not think that it will make THAT much of a difference.
If you use a AV, install all updates ect,... you should be ok,....
but again,...why switch to Windows Vista if Windows XP SP2 runs pretty OK.
I know people that own Windows 98 SE and basically they are sometimes "more secured" then a WinXP user. (some new virusses do not work on the 98 systems,...)
Anyway,...its good that Avast! is also guaranteed to work on Vista,...