Vista 32-bit or 64-bit

So, I am in the process of building a new Windows box as my current one is about dead (fortunately, my Linux box still functions well) and am planning on installing Vista so that I do not have to worry about not being able to run new software in a year or two. However, I have noticed that the HCL (Hardware Compatibilty List) that I found seems to be rather sparse.

This seems odd to me, why would Microsoft release an Operating System that will not run well - or at all - on many computers? Another question is why hardware manufacturers would not have released more drivers by now?

I don't want to run a 32-bit Operating system on a 64-bit processor as I am a programmer by vocation and would like to be able to test 64-bit versions of my programs. However, I also do not want to waste money on an Operating System that will not work with my hardware, or spend hours weeding through New Egg trying to find hardware that is guaranteed to work correctly with Vista 64-bit.

Has anyone had good luck with Vista 64-bit? I would like to think that the HCL that I was reading was outdated, and that a newer version lists many more devices.