again ... I consider buying a new box for work.

currently I am still quite happy with my core2duo E6600 with 8 gigs of
ram, running ~amd64 ... running fine.

but I remember the huge step back then from the pentium 4 ...

Will it be the same when I go for a core i5?

I use that box for virtualization as well (vmware and kvm), so maybe it
would also help to not only change cpu but also add 2 cores (going
quadcore).

I just want to hit the sweet spot if that's possible.

And I'd like to hear any pros and cons if you would like to share.

Thanks, Stefan