I'm not sure who disagrees with who, but it seems we all agree.
64 bit is needed for the extra RAM. In fact, our Core i7, also a quad core routinely goes over 5 GB with Premiere alone, so a 32 bit system could not take advantage of it.
And if you use After Effects, you'll need even more RAM.
As for degradation in performance, I believe this is referring to older applications running Microsoft emulation layer, not the case for Premiere.
There is in the end more overhead in running a 64 bit system, but being limited to less than 4 Gigs of RAM is not an option for us any more.
Vince Becquiot
Kaptis Studios
San Francisco - Bay Area