It's a part of a CPU design that most will note. FYI, most video cards have 64, 128 and even 256 bit wide data paths since... you can move more with more lanes to move on.
The 2005 view is that dual-core 64-bit capable units will cost about the same as today's machines. My advice is always to wait if you can and never overspend.
Are we talking about Ram here. I always associated 32 bits with my display adapter.