Talk me about 64 bit systems...

Suppose you just buy a new piece of computer, with 64 bit technology and everything you consider cool. And suppose you'd like to install a GNU/Linux system on it.

As you've got a 64 bit architecture, I think you should use a 64 bit distribution, right? Once you installed it, since the 32 bit instruction set should be still available, you should be able to run 32 bit applications as well.

The only thing that may prevent you to run it would be the use of shared libraries, since a 32 bit application could never dinamically load a 64 bit shared library...

Is there a leak in my reasoning?

Well... I've just read this article: http://www.linuxforums.org/forum/linux-tutorials-howtos-reference-material/69585-should-you-choose-32-bit-64-bit-linux.html

And actually there seems no real reason to use a 64 bit distribution... so that why should I buy a 64 bit computer then? And most importantly, am I able to find a 32 bit computer here around?