Windows Vista isn’t actually too slow if you have enough memory and good cpu. It’s just important that it doesn’t have to use virtual memory and so. I know this sounds funny but I bought 8GB of DDR2 memory and it works very well. DDR2 800 Mhz is very cheap these days, only about 10 euros (10-15 dollars?) per giga so I decided to buy 8GB. I have turned of pagefile.sys or whatever it was so everything runs smoothly in my Vista.
One annoying thing in Vista is that elevation thing which is very annoying in some things especially if you want to run installer inside compressed file. Some times you have to run notepad or commandline as super user to do some simple changes to some files.