You may have missed this interesting blog post this morning amidst all the political kerfuffle, so let me sum up: the next version of OCS will only support x64 platforms.
This isn't the big deal it would have been for OCS 2007. A lot of the initial FUD around the 64-bit-only move in Exchange 2007 turned out to be mere steam. While there were some initial challenges involved in managing the new 64-bit Exchange deployment from 32-bit machines, Microsoft got a lot of the licensing figured out and released the appropriate sets of tools to allow management of Exchange 2007 from both 32-bit and 64-bit environments. I fully expect that the OCS group has been paying close attention to all of this and taken good notes.
There's no denying that Exchange 2007 benefits from the "64-bit only in production" stance -- and with the release of Windows Server 2008 and Hyper-V, not to mention Microsoft's updated support statement for virtualization environments, the need for 32-bit environments is going away. My biggest reason for wanting 32-bit Exchange environments was so I could run demos under Virtual Server; now that I have Hyper-V, I'm probably not in any rush to go back to Virtual Server and the 32-bit limitation. 64-bit hardware is the norm today, and the x64 Windows variants are solid and mainstream enough for my dedicated application servers. (Maybe not so for the desktop quite yet, but still getting there rapidly.)
The one thing I'm skeptical about, though, is whether the move to 64-bits is really going to reduce the total number of servers in the deployment. In Exchange 2007, I only saw the server reductions in very large environments; the mailbox-per-server gains we got from 64-bits was offset by the explicit breakout of roles and the business needs that drove redundant configurations like CCR (which meant no co-locating roles with the Mailbox role) and multiple HT/CAS servers. I'm wondering how this is going to play out with the next version of OCS, where it already has so many distinct roles in play.
What I *hope* to see is that the maximum capacity of each server role (such as the number of users per pool or the number of streams per mediation server) can be driven upwards; this makes the large datacenter configuration options much more attractive, because it does translate to a reduced number of servers. However, for organizations that still have relatively low bandwidth separating their various locations, 64-bits won't do much to help; OCS deployment planning is very dependent on bandwidth, and is often the top limit on scalability long before the limits of the 32-bit Windows environment.