As I mentioned in this older post, After Effects CS5 will be a native 64bit program, which is some people’s most wanted feature, others’ most dreaded one. Reasons for fearing this day go far and wide from being stuck with an older computer that cannot be outfitted with 64bit-ness to issues with Quicktime to simply losing support for third-party plug-ins. None of that is of course true. Quicktime will work and most commercial plug-ins should be available as compatible versions by the time the product is released or shortly thereafter. So, by all means, collateral damage on that end should not be a problem. You may just need to part ways with some free plug-ins, as the developers may not have the time, resources and interest to update them.