Do I need it?
If you have to ask this question, then the answer is probably no. As far as gaming is concerned, there is no compelling reason to swicth to x64 from a performance point of view. You shouldn't experience any compatability issues with your 'old', 32bit games, but that doesn't mean you wont, and there's certainly no performance gain to justify the move. Specific applications that can benefit from the 64bit extensions provide a stronger appeal for those that use them. If you rely on virtualisation software, or program compilers for instance, there are applications out there which will directly benefit from a native 64bit environment - and in theory run faster.
This isn't to say that, if you dont use any of these applications, you couldn't see any benefit from the x64 editions, if you have a suitable setup. Systems with 2gb of memory plus, or SMP (multi-processor/core) systems for instance could see a noticeable benefit by running x64 - however it isn't a black and white decision. The first hurdle you need to overcome is finding drivers for all your hardware, which might not be as easy as you'd hope. Drivers for x64 are gaining in number as the weeks go by, so check out the links in our archived x64 thread to see if you can turn one up.
The other thing to consider, is that compared to the 32bit versions of Windows, x64 is very much a product in its infancy, and there is a significantly smaller amount of information available on the internet, possibly making it harder to find support if you need it. This is much more of a concern with third party applications, rather than the OS itself. If you're running some 32bit software on x64 and stumble across a bug - it's unlikely you'll get support from the developers if they dont officially support the platform.
Many people (myself included) report very few, if any problems when it comes to 32bit emulation, but it's still a chance you take.
