First, ask yourself:
- What is a "64-bit application"?
- What advantages does such an application offer?
- What are the disadvantages?
In talking to lots of customers, I find that most are unable to answer these questions. (There’s nothing inherently wrong with that. As I’ve said, I myself am just a simple unfrozen caveman Web designer, and like most non-engineers I don’t presume to grok the intricacies of complex software design.) Yet despite the lack of widespread understanding, "64 bit" is one of those buzzwords (a la "Cocoa" and many others) that sounds cool, eliciting a lot of "arewethereyet, arewethereyet??" that may or may not be warranted.
Photoshop co-architect Scott Byer has posted a lucid, readable overview of 64-bit computing & where Photoshop stands relative to this transition. Given a great number of factors, we elected not to make the change in this cycle. That said, Photoshop does take advantage of some aspects of 64-bit chips, and as Scott notes, "It’s a when, not an if" we’ll make the move. His info should help cut through some of the hype & set reasonable expectations about the future.