What I mean by "can":
CPU that supports 64 bits - check (dual cores AMD or Intel)
O/S that supports 64 bits - check (MS O/S and Linux both have 64 bits versions)
Motherboard that supports 64 bits???
Chipset that supports 64 bits???
What I mean by general desktop:
I don't want to pay the premium for "server systems". So whatever is not considered server would be "general desktop" to me.
More generally, I use my desktop for the usual general purpose stuff. Some business use (software development, office apps, very high res - meaning large size - photo handling), some personal use, some game. I like my system to be strong enough to last around 5 years. So I tend to get a fairly high power system, then add more RAM along the way. That way it'll be good enough to still be usable in 5 years. My current system is now 5 years old. It's pretty slow now, but still mostly serviceable. Looking ahead 5 years, I can see that RAM requirements will probably exceed 4 GB in fairly short order. So I'm wondering to upgrade now, or wait until I can get a system that will handle more than 4 GB for future upgrades.