Why?
Why would you even bother with a petition like this? What's the point? It's almost as stupid as actually buying the software and installing it.
There are precisely zero reasons for buying Vista. Nothing works better in Vista than it does under XP. That's nothing, zero, zilch.
Security? Microsoft? You're having a laugh right? You'd buy a Microsoft operating system prior to it's first service pack to improve security?
So what you want is to cripple your computer's performance for the sake of eye candy. Eye candy that can be downloaded and installed for next to nothing already. And it's just as efficient at slowing your computer down and making it more unstable as the real thing.
I don't own a Mac, I don't use Linux - so just to make this clear I am a Windows user. I recently bought my kids a dual core 64-bit system.
It was average, nothing special, fairly cheap actually. I improved it's performance in all their games and applications by over 30% by moving from the supposedly 64-bit OS to regular XP Pro. Not even the 64-bit version (that's mostly because there are almost zero 64-bit games or applications for Windows - there are a couple and a few in development, but we don't own a single one).
World of Warcraft, their almost exclusive use for this computer, performs so much better they asked if I'd bought them a new processor, more ram and a top of the range video card.
But what about the future? Eventually we'll be forced to move to Vista won't we, and where we will be if we follow your advice and stick with XP?
Let's start with the fact you don't pay more than $50 for an OEM operating system (if you buy the PC from a manufacturer that includes the OS). Let's also see what happens if no one buys Vista for $200-$400 a pop. Want to bet the prices might fall just a tad.
No protesting to the government that Vista costs too much is almost as pointless as complaining Sony overpriced the PS3. They did, but that's not why it won't sell - it won't sell because there's absolutely no point in buying one unless you want a blu-ray player. The games are bland and unimaginative, and nothing you haven't seen a dozen times on any other system built in the last decade.
Actually I'm starting to think Microsoft are deliberately taking the piss. If it wasn't bad enough they opened up our computers to performance crippling malware, they thought they'd cut out the middle man and simply kill the performance of the computer just by installing the OS.
Don't buy Vista - it's unqualified shit.