32 or 64 bit?

[Nik N]

>> Do you need to virtualize? I found a while ago that me -- using a low
>> segment Core 2 Duo -- cannot virtualize on a 64 bit system because my
>> Core 2 Duo lacks virtualization extensions.
>> Do check if you have them in case you need them.
>
>    What do you mean ? You can virtualize if you stick to 32bit and
>  not if you go to 64bit ? I had not heard anything like that before.
>
I use VirtualBox a lot and have tested it (under 64-bit ubuntu 9.04); it
works well (with 32-bit guests, both XP & various 32-bit Linuxes  - I have
no interest in ever running  64-bit guests).

I have 4 GB of memory, and this is so far the only reason I'm considering
64-bit system. (is it true that 32-bit 9.10 will work with all 4, but only the
applications will be restricted to 3 (or less)? Correct? (yes/no?)

Everything else so far - application software and hardware  drivers'
stability specifically - appears to points to the 32-bit OS.

Thank you all for your comments! Any other?
Nik N.