Advice on changing to 64 bits

[Klaus-Peter Schrage]

Up to last week, I had Fedora running in subsequent versions 2 or so to 
10 on my old Pentium 4 system.

Now I have a rather recent new desktop computer with much of the latest 
and greatest hardware: Intel Core 2 Duo E8400 with 4 GB RAM, harddrive 
with lots of Gagabytes and so on.

Thinking about changing to 64 bits architecture (I have the i386 
installation dvd, but not yet the i86_64 one), I was astonished how 
little I found on pros and cons. So what would you advise?

1. Changing to 64 bits is a must for you.
2. You will benefit from it.
3. Keep your hands off, stay with 64 bits.
4. ...

I should mention that I want to use virtualization (KVM, VMware Server), 
and that the processor has Intel's hardware vitualization capabilities.

Thanks for any pointers.
Klaus