Well I am not a software developer but I can tell you from my professional experience in IT, that 64bit is not anywhere near being a standard platform for windows. Developers have not released support for it yet. Vista has been in production for over 6 years and released for over 9 months and driver support still sucks for it. Having over 3.25gigs of RAM does not even improve system performance unless you are actually using all of it. Also, since Vista is also the biggest flop of upgrades and major companies like HP and Dell and Lenevo have decided to let their customer's get XP on their systems still and people are still gettting it, there is no pressure on the developers to even start making 64bit applications.
Just because you can argue it is more "future proof" really means squat with technology. Anyone could have argued that with any technology that has failed, but looked good on paper when it first came out. EDO RAM, RAMBUS, laser disk, mini disk, beta max, cat3, IPX, so on and so forth.
What application or game will take up more than 4 gigs of RAM? To the point where you are having to access so much virtual memory it slows your system down? I don't even think you understand how memory access works in a computer Thatguy16, and I am not trying to call you out or dis you but you don't provide any facts with any of your advice.
Given Microsoft's track record, the fact that Vista has extremely high system requirements and overall is kind of a crappy OS compared to all other OSes currently out, given that it has been out for 9 months and in production for 6 years and given its current state I would say it is a no brainer. Driver support is not only buggy, but also absent in 64bit windows. This includes both 64bit XP and 64bit Vista. I have the 64bit version of Vista Business on my work desktop and have been using it since relase (beta before that) and I have had tons of issues getting devices that work flawlessly in XP to work with it. I was asked by our IT director to test out vista, so I did. I installed it, added all of our supported technology to it, on a system which should be able to handle it, and have had nothing but issues on it. Being able to run 4gigs of RAM would not fix any of my issues.