I run both X86 and X64.
X64 is installed on 2 machines just because they run some home-made apps which have been developped especially for Vista 64 bit which need hell of a lot of memory.
On all other machines, i run X86 mainly because i do not use 64 bit applications and even sometimes some old apps which run on X86 but not at all on X64.
Some hardware are also not at all compliant with X64, for example a TV sat PCI card, a quite old sound card but giving fantastic results, etc....
You have to know that most of the well known apps are designed mainly to work on X86 and are "adapted" to work on X64, only the specific applications are designed for X64, in that case the editor will give you the choice between the 2 versions.
So really it depends of the use of your machine but if you do not need especially to run real 64 bit apps, i would suggest 32 bit.... It is just my point of view.
The reliability monitor gives me 10 on all 32 bit machines, on the 2 64 bit they navigate between 5 and 7
I am waiting Vista 7 (next year ?), i think we will have some good surprises at this time.
BTW, the article is quite good, i mean writen a good way, you can find thousands of articles writen by experts which tell the exact opposite.... and for those who say: Yes but in the near future you will see that you are wrong, i just say that in the near future Vista won't exist anymore